Backport#24912

This pull request includes several changes to thesrc/System.Management.Automation/security/wldpNativeMethods.cs file to improve the handling of system lockdown policies and file policy enforcement. The changes primarily focus on refining the logic for determining enforcement modes and handling exceptions more effectively.

Key changes include:

Improvements to system lockdown policy handling:

• Modified theGetSystemLockdownPolicy method to use an out parameter forGetDebugLockdownPolicy.
• Added a new methodConvertToModernFileEnforcement to convert legacy enforcement modes to modern file enforcement modes.

Enhancements to file policy enforcement:

• Updated theGetFilePolicyEnforcement method to use the newConvertToModernFileEnforcement method and added logic to handle different enforcement scenarios more accurately.
• Introduced theTryGetWldpCanExecuteFileResult method to handle the result ofWldpCanExecuteFile and fallback to legacy APIs if necessary.

Exception handling improvements:

• Refined the exception handling inGetFilePolicyEnforcement to catch bothDllNotFoundException andEntryPointNotFoundException and log the appropriate events.

Additional minor changes:

• AddedSystem.Diagnostics using directive for better debugging support.
• Adjusted theGetDebugLockdownPolicy method to use an out parameter for modern enforcement.[1][2][3]

These changes collectively enhance the robustness and accuracy of the system's lockdown policy and file enforcement mechanisms.