AdfsGlobalAuthenticationPolicy: Add Integration Tests

[X-Guardian]

Pull Request (PR) description

This PR adds integration tests for the AdfsGlobalAuthenticationPolicy resource.

This Pull Request (PR) fixes the following issues

• None

Task list

• [x] Added an entry under the Unreleased section in the CHANGELOG.md. Entry should say what was changed, and how that affects users (if applicable).
• [ ] Resource documentation added/updated in resource directory README.md.
• [ ] Resource parameter descriptions added/updated in schema.mof and comment-based help.
• [ ] Comment-based help added/updated.
• [ ] Localization strings added/updated in all localization files as appropriate.
• [ ] Examples appropriately added/updated.
• [ ] Unit tests added/updated. See DSC Resource Testing Guidelines.
• [x] Integration tests added/updated (where possible). See DSC Resource Testing Guidelines.
• [x] New/changed code adheres to DSC Resource Style Guidelines and Best Practices.

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This change is 

[codecov[bot]]

Codecov Report

Merging #29 into dev will not change coverage. The diff coverage is n/a.

@@          Coverage Diff          @@
##             dev     #29   +/-   ##
=====================================
  Coverage   98.3%   98.3%           
=====================================
  Files         16      16           
  Lines       2123    2123           
=====================================
  Hits        2087    2087           
  Misses        36      36

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