CmdPal: collection of Run Commands nits (#42092)

* Path items were being treated inconsistently
* We shouldn't re-enumerate a directory on every keystroke
* A bunch of elements had empty TextToSuggest (which makes it crazier
  that it ever worked right)


Vaguely regressed in #41956
related to #39091

.pipelines/verifyCommonProps.ps1

@@ -44,6 +44,9 @@ foreach ($csprojFile in $csprojFilesArray) {
     if ($csprojFile -like '*Microsoft.CmdPal.Core.*.csproj') {
         continue
     }
+    if ($csprojFile -like '*Microsoft.CmdPal.Ext.Shell.csproj') {
+        continue
+    }
 
     $importExists = Test-ImportSharedCsWinRTProps -filePath $csprojFile
     if (!$importExists) {