Connect-DbaInstance: Fix for issue when changing database context

[andreasjordan]

Type of Change

• Bug fix (non-breaking change, fixes # )
• New feature (non-breaking change, adds functionality, fixes # )
• Breaking change (affects multiple commands or functionality, fixes # )
• Ran manual Pester test and has passed (.\tests\manual.pester.ps1)
• Adding code coverage to existing functionality
• Pester test is included
• If new file reference added for test, has is been added to github.com/dataplat/appveyor-lab ?
• Unit test is included
• Documentation
• Build system

The problem was discovered while working on the test for Remove-DbaDbTableData. Inside of Backup-DabaDatabase changing the database context to master was not possible and resulted in using a cached connection to an already dropped database.

In the first commit, I added a test inside of Connect-DbaInstance to write a warning:

if ($Database -and $server.ConnectionContext.CurrentDatabase -ne $Database) {
    Write-Message -Level Warning -Message "Changing connection context to database $Database was not successful. Current database is $($server.ConnectionContext.CurrentDatabase). Please open an issue on https://github.com/dataplat/dbatools/issues."
}

In the second commit I added a test to show the warning:

In the third commit, I implement the fix, changing $connContext = $connContext.GetDatabaseConnection($Database) to $connContext = $connContext.GetDatabaseConnection($Database, $false).

[potatoqualitee]

I really like this solution, thank you!