`Install-SqlServerDsc`: AgtSvcAccount no longer needed for `Install`

[bleakprestiger]

Pull Request (PR) description

• Removed Install Keyword from the if condition present in the SqlServerDsc/source/Private/Assert-SetupActionProperties.ps1 Script.
• Updated CHANGELOG.md Regarding appropriate Changes.
• Updated Assert-SetupActionProperties.Tests for updating the test cases.

This Pull Request (PR) fixes the following issues

• Fixes #1810

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).
• [ ] Resource documentation updated in the resource's README.md.
• [ ] Resource parameter descriptions updated in schema.mof.
• [ ] Comment-based help updated, including parameter descriptions.
• [ ] Localization strings updated.
• [ ] Examples updated.
• [ ] Unit tests updated. See DSC Community Testing Guidelines.
• [ ] Integration tests updated (where possible). See DSC Community Testing Guidelines.
• [ ] Code changes adheres to DSC Community Style Guidelines.

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This change is 

[codecov[bot]]

Codecov Report

Merging #1814 (46101fa) into main (a512eff) will not change coverage. The diff coverage is 100%.

@@         Coverage Diff          @@
##           main   #1814   +/-   ##
====================================
  Coverage    88%     88%           
====================================
  Files        83      83           
  Lines      7444    7444           
====================================
  Hits       6594    6594           
  Misses      850     850           

Flag	Coverage Δ
unit	88% <100%> (ø)

Impacted Files	Coverage Δ
source/Private/Assert-SetupActionProperties.ps1	98% <100%> (ø)

[bleakprestiger]

Thanks @johlju

[johlju]

Great work on this!