PR Summary

This PR addresses the issue described in#745. When modules are installed during a document being applied, the subsequent modules that are checked in the cache are overwritten. Example:

1. The first run initiates the resource cache (dsc resource list) as no cache is found.
2. The first configuration is applied, installing new PowerShell modules (triggering the cache on module paths to be stale).
3. The assertion triggers theInvoke-DscCacheRefresh -Module '<module>', flushing out the cache with only that particular module.
4. Modules underneath aren't found anymore in the same sequence.

It's a pretty rough edge case and quite interesting to debug. Nevertheless, there isn't any test added because it would either introduce an external dependency or require internal work to be implemented. Of course, I can be wrong on this and would appreciate some help to write one.