This PR fixes a bug reported offline by@jeffhandley ```logfail: Microsoft.Extensions.DataIngestion.IngestionPipeline[6]      An error occurred while ingesting document 'Example_GPS_Watch.md'.      System.InvalidCastException: Unable to cast object of type 'System.Guid' to type 'System.String'.         at System.Linq.Enumerable.CastICollectionIterator`1.MoveNext()         at Azure.Search.Documents.Models.IndexDocumentsBatch.Delete(String keyName, IEnumerable`1 keyValues)         at Azure.Search.Documents.SearchClient.DeleteDocumentsAsync(String keyName, IEnumerable`1 keyValues, IndexDocumentsOptions options, CancellationToken cancellationToken)         at Microsoft.Extensions.VectorData.VectorStoreErrorHandler.RunOperationAsync[TResult,TException](VectorStoreCollectionMetadata metadata, String operationName, Func`1 operation)         at Microsoft.Extensions.DataIngestion.VectorStoreWriter`1.WriteAsync(IAsyncEnumerable`1 chunks, CancellationToken cancellationToken)         at Microsoft.Extensions.DataIngestion.IngestionPipeline`1.IngestAsync(IngestionDocument document, Activity parentActivity, CancellationToken cancellationToken)         at Microsoft.Extensions.DataIngestion.IngestionPipeline`1.ProcessAsync(IEnumerable`1 files, Activity rootActivity, CancellationToken cancellationToken)+MoveNext()```---------Co-authored-by: Shay Rojansky <roji@roji.org>

This PR fixes the issue when an MCP function is called with an argumentthat doesn't match the expected parameter type.From chat:```csharppublic async Task<string> GetDataAsync(    [Description("Optional modality type filter (CT, MRI, XA, etc.). Make sure it is a LIST of strings. Examples: ['CT'] or ['CT', 'MR']")] List<string>? modalityType = null, (...............)```When we tested it using Semantic Kernel without MCP, it returned thedata in the correct format. However, when we integrated it into the tool(one API Server where we initialize the Kernel and another MCP Serverwith all the functions), we get the incorrect format:<img width="1186" height="175" alt="image"src="https://github.com/user-attachments/assets/9efd26e2-77fc-4ec2-85ed-60a35fa9e821"/>

### Motivation and Context<!-- Thank you for your contribution to the semantic-kernel repo!Please help reviewers and future users, providing the followinginformation:  1. Why is this change required?  2. What problem does it solve?  3. What scenario does it contribute to?  4. If it fixes an open issue, please link to the issue here.-->Agent failure results in timeout for `OrchestrationResult`.Fixes:#13149Fixes:#13040Fixes:#12987### Description<!-- Describe your changes, the overall approach, the underlying design.These notes will help understanding how your code works. Thanks! -->`AgentActor` exception being eaten by the agent-runtime and not exposedvia the `TaskCompletionSource<>` used by the `OrchestrationResult`/### Contribution Checklist<!-- Before submitting this PR, please make sure: -->- [X] The code builds clean without any errors or warnings- [X] The PR follows the [SK ContributionGuidelines](https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md)and the [pre-submission formattingscript](https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md#development-scripts)raises no violations- [X] All unit tests pass, and I have added new tests where possible- [X] I didn't break anyone 😄

### Motivation and Context<!-- Thank you for your contribution to the semantic-kernel repo!Please help reviewers and future users, providing the followinginformation:  1. Why is this change required?  2. What problem does it solve?  3. What scenario does it contribute to?  4. If it fixes an open issue, please link to the issue here.-->Closes#12970,#13352### Description<!-- Describe your changes, the overall approach, the underlying design.These notes will help understanding how your code works. Thanks! -->1. Migrate Google AI connector to use the new Google AI SDK.2. This PR also marks the VertexAI connector as deprecated in favor ofthe Google AI connector. With this update, if users wants to connect toa VertexAI project instead of a Google AI endpoint, they can do so withthe Google AI connector.3. This PR also adds the ability for users to provide a custom client tothe Google AI connector (#13352).4. This PR also marks `AzureTextCompletion` deprecated.### Contribution Checklist<!-- Before submitting this PR, please make sure: -->- [x] The code builds clean without any errors or warnings- [x] The PR follows the [SK ContributionGuidelines](https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md)and the [pre-submission formattingscript](https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md#development-scripts)raises no violations- [x] All unit tests pass, and I have added new tests where possible- [ ] I didn't break anyone 😄

### Motivation and ContextBump to v1.39.0 for a release<!-- Thank you for your contribution to the semantic-kernel repo!Please help reviewers and future users, providing the followinginformation:  1. Why is this change required?  2. What problem does it solve?  3. What scenario does it contribute to?  4. If it fixes an open issue, please link to the issue here.-->### DescriptionBump to v1.39.0 for a release<!-- Describe your changes, the overall approach, the underlying design.These notes will help understanding how your code works. Thanks! -->### Contribution Checklist<!-- Before submitting this PR, please make sure: -->- [X] The code builds clean without any errors or warnings- [X] The PR follows the [SK ContributionGuidelines](https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md)and the [pre-submission formattingscript](https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md#development-scripts)raises no violations- [X] All unit tests pass, and I have added new tests where possible- [ ] I didn't break anyone 😄