[TypeSpec Validation] Fixes "trigger on only specification/<service-f…

…amily> (#26276)" (#26321)

* test

* fix

* cleanup

* fix checkall scenario

* testing

* cleanup

* cleanup

* test run

* test run

* test run

* Revert "test run"

This reverts commit 06ba8db.

* Revert "test run"

This reverts commit a0f024a.

* Revert "test run"

This reverts commit fe26671.

eng/scripts/Get-TypeSpec-Folders.ps1

@@ -7,7 +7,7 @@ Set-StrictMode -Version 3
 . $PSScriptRoot/ChangedFiles-Functions.ps1
 
 $repoPath = Resolve-Path "$PSScriptRoot/../.."
-$checkAllPath = "specification"
+$checkAllPath = ((Get-ChildItem "specification" -Directory).Name -replace '^', 'specification/') -replace '$', '/'
 
 if ($CheckAll) {
   $changedFiles = $checkAllPath
@@ -28,9 +28,9 @@ else {
 $typespecFolders = @()
 $skippedTypespecFolders = @()
 foreach ($file in $changedFiles) {
-  if ($file -match 'specification(\/[^\/]*\/)*') {
+  if ($file -match 'specification(\/[^\/]+\/)+') {
     $path = "$repoPath/$($matches[0])"
-    if (Test-Path $path) {   
+    if (Test-Path $path) {
       Write-Verbose "Checking for tspconfig files under $path"
       $typespecFolder = Get-ChildItem -path $path tspconfig.* -Recurse
       if ($typespecFolder) {