chore: Clean up code

[johlju]

Pull Request (PR) description

• Some code cleanup.
• Fix incorrect position value in Get-PesterCommandParameter.
• Update PowerShell version requirement to 7.1.

This Pull Request (PR) fixes the following issues

None.

Task list

• 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).
• Documentation added/updated in README.md and source/WikiSource.
• Comment-based help added/updated for all new/changed functions.
• Localization strings added/updated in all localization files as appropriate.
• Examples appropriately added/updated.
• Unit tests added/updated. See DSC Community Testing Guidelines.
• Integration tests added/updated (where applicable). See
  DSC Community Testing Guidelines.
• New/changed code adheres to DSC Community Style Guidelines.

---

This change is 

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99%. Comparing base (42526bf) to head (19ffa20).

Additional details and impacted files

@@         Coverage Diff         @@
##           main    #29   +/-   ##
===================================
- Coverage    99%    99%   -1%     
===================================
  Files        29     29           
  Lines      1208   1172   -36     
===================================
- Hits       1205   1169   -36     
  Misses        3      3           

Flag	Coverage Δ
unit	99% <100%> (-1%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
source/Private/Convert-ShouldBe.ps1	100% <100%> (ø)
source/Private/Convert-ShouldBeExactly.ps1	100% <100%> (ø)
source/Private/Convert-ShouldBeFalse.ps1	100% <100%> (ø)
source/Private/Convert-ShouldBeGreaterOrEqual.ps1	100% <100%> (ø)
source/Private/Convert-ShouldBeGreaterThan.ps1	100% <100%> (ø)
source/Private/Convert-ShouldBeIn.ps1	100% <100%> (ø)
source/Private/Convert-ShouldBeLessOrEqual.ps1	100% <100%> (ø)
source/Private/Convert-ShouldBeLessThan.ps1	100% <100%> (ø)
source/Private/Convert-ShouldBeLike.ps1	100% <100%> (ø)
source/Private/Convert-ShouldBeLikeExactly.ps1	100% <100%> (ø)
... and 10 more