Tests requiring EXO or SPO must not be run in parallel. (#1361)

The current check only does this for _all_ Data pillar tests, or tests
that use SecurityCompliance service. This change adds EXO, SPO and AIP to the
SecurityCompliance as services.

Potential further improvement - completely remove the Pillar check and
only leave the required services check. This is more reliable and even
can have the side effect of pushing Data checks to parallel if there is
now (or in the future) such that only use Graph or Azure.

Addresses #1360

Author: astaykov

src/powershell/private/tests/Invoke-ZtTests.ps1

@@ -111,18 +111,24 @@
 	$skippedTestsForService.ForEach{
 		$notConnectedService = ($_).Service.Where{ $_ -notin $ConnectedService }
 		# Mark the test as skipped.
+		Write-PSFMessage -Message ('Test {0} is skipped because no service connection was found' -f $_.TestId) -Level Verbose
 		Add-ZtTestResultDetail -SkippedBecause NotConnectedToService -TestId $_.TestId -NotConnectedService $notConnectedService
 	}
 
 	$testsToRun = $testsToRun.Where{ $_.TestId -notin $skippedTestsForService.TestId }
 
-	# Separate Sync Tests (Compliance/ExchangeOnline/SharePointOnline) from Parallel Tests (because of DLL order to manage in runspaces & remoting into WPS)
-	# Tests that depend on SecurityCompliance remoting must run on the main thread regardless of pillar.
-	[int[]]$syncTestIds   = $testsToRun.Where{
-		$_.Pillar -contains 'Data' -or $_.Service -contains 'SecurityCompliance'
-	}.TestId
-	$syncTests     = $testsToRun.Where{ $_.TestId -in $syncTestIds }
-	$parallelTests = $testsToRun.Where{ $_.TestId -notin $syncTestIds }
+	# Separate Sync Tests (Compliance/ExchangeOnline/SharePointOnline/AIP) from Parallel Tests (because of DLL order to manage in runspaces & remoting into WPS)
+	# Tests that depend on SecurityCompliance/ExchangeOnline/SharePointOnline/AIPService must run on the main thread
+	# regardless of pillar: those services expose their cmdlets through dynamically-generated, connection-bound
+	# proxy modules (Connect-IPPSSession / Connect-ExchangeOnline / Connect-SPOService / Connect-AipService) that only exist in the
+	# main runspace where Connect-ZtAssessment ran. In a worker runspace those cmdlets are "not recognized",
+	# so such tests would incorrectly skip (e.g. Get-SafeLinksPolicy, Get-OrganizationConfig, Get-SPOTenant).
+	$mainThreadServices = 'SecurityCompliance', 'ExchangeOnline', 'SharePointOnline', 'AipService'
+
+	$syncTests, $parallelTests = $testsToRun.Where({
+		$_.Pillar -contains 'Data' -or
+		@($_.Service).Where({ $_ -in $mainThreadServices })
+	}, 'Split')
 
 	[dateTime] $startTime = [datetime]::Now
 	$workflow = $null