Add Assert-SqlLogin command to validate SQL Server login existence#2121

Copilot wants to merge 1 commit intomaindsccommunity/SqlServerDsc:mainfrom

copilot/fix-ab127889-8caa-48e5-8019-33f3c2d47b64dsccommunity/SqlServerDsc:copilot/fix-ab127889-8caa-48e5-8019-33f3c2d47b64Copy head branch name to clipboard