xRDSessionCollection: Resolve Issue 106; always filter Get-RDSessionCollection result set

[uw-dc]

Pull Request (PR) description

RDSessionCollection's Get-TargetResource has been amended so that it filters the RD Session Collections returned from Get-RDSessionCollection on CollectionName matching the desired $CollectionName, in all circumstances.

PR also contains an attempt to improve the testing in this area.

This Pull Request (PR) fixes the following issues

• Fixes #106

Task list

• [x] Added an entry to the change log under the Unreleased section of the file CHANGELOG.md. Entry should say what was changed and how that affects users (if applicable), and reference the issue being resolved (if applicable).
• [ ] Resource documentation added/updated in README.md.
• [ ] Resource parameter descriptions added/updated in README.md, 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.
• [x] Unit tests added/updated. See DSC Community Testing Guidelines.
• [ ] Integration tests added/updated (where possible). See DSC Community Testing Guidelines.
• [x] New/changed code adheres to DSC Community Style Guidelines.

---

This change is 

[codecov[bot]]

Codecov Report

Merging #107 (784843c) into master (b97c82b) will increase coverage by 0%. The diff coverage is 100%.

@@          Coverage Diff          @@
##           master   #107   +/-   ##
=====================================
  Coverage      88%    89%           
=====================================
  Files           9      9           
  Lines         461    470    +9     
=====================================
+ Hits          410    419    +9     
  Misses         51     51           

Impacted Files	Coverage Δ
...RDSessionCollection/MSFT_xRDSessionCollection.psm1	96% <100%> (+1%)	:arrow_up:

[uw-dc]

if #109 is merged, this PR can be deleted