SqlServerLogin: Added integration tests

[johlju]

Pull Request (PR) description

• Changes to xSqlServerLogin
  • Added integration tests (issue SqlServerLogin: Integration test is missing for this resource #748).

This Pull Request (PR) fixes the following issues:
Fixes #748

Task list:

• Change details added to Unreleased section of CHANGELOG.md?
• Added/updated documentation, comment-based help and descriptions in .schema.mof files where appropriate?
• Examples appropriately updated?
• New/changed code adheres to Style Guidelines?
• Unit and (optional) Integration tests created/updated where possible?

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This change is 

[codecov-io]

Codecov Report

Merging #998 into dev will not change coverage.
The diff coverage is n/a.

@@         Coverage Diff         @@
##            dev   #998   +/-   ##
===================================
  Coverage    97%    97%           
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  Files        32     32           
  Lines      3904   3904           
===================================
  Hits       3817   3817           
  Misses       87     87

[johlju]

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Reviewed 4 of 4 files at r1.
Review status: all files reviewed at latest revision, all discussions resolved.

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Comments from Reviewable

[johlju]

Merging this one so I can get the other PR thru.