Fix Show Installed Apps reliability and selection (#4850)

* Fix Windows PowerShell runspace cleanup callback

* Fix installed app package ID matching

* Synchronize installed app selection UI

* Streamline installed app detection

* Avoid installed app UI runspace deadlock

functions/public/Invoke-WPFSelectedCheckboxesUpdate.ps1

@@ -7,11 +7,21 @@ function Invoke-WPFSelectedCheckboxesUpdate ($type, $checkboxName) {
         '^WPFAppx'    { 'selectedAppx' }
     }
 
+    $selectionChanged = $false
     if ($type -eq "Add") {
         if (-not $sync.$listName.Contains($checkboxName)) {
             $sync.$listName.Add($checkboxName)
+            $selectionChanged = $true
         }
     } else {
-        $sync.$listName.Remove($checkboxName)
+        $selectionChanged = $sync.$listName.Remove($checkboxName)
+    }
+
+    if ($listName -eq "selectedApps" -and $selectionChanged) {
+        $sync.WPFselectedAppsButton.Content = "Selected Apps: $($sync.selectedApps.Count)"
+        $sync.selectedAppsstackPanel.Children.Clear()
+        $sync.selectedApps | Sort-Object | ForEach-Object {
+            Add-SelectedAppsMenuItem -name $sync.configs.applicationsHashtable.$_.Content -key $_
+        }
     }
 }