Expand Pester coverage across install, tweaks, and UI workflows (#4792)

* Harden Pester CI and discard runspace return values

* Add prioritized test backlog

* Add WinUtil action logging

* Add config integrity tests

* Add XAML control wiring tests

* Add registry and service helper tests

* Add package manager tests

* Add runspace behavior tests

* Add tweak orchestration tests

* Add install workflow tests

* Add update profile tests

* Add AppX removal tests

* Log package installer output

* Add UI state helper tests

* Pin Pester test runner version

* Expand Win11 Creator tests

* Add preferences and theme tests

* Add search filter tests

* Add compile contract tests

* Use single WinUtil session log

* Remove installer output logging helper

* Handle locked WinUtil transcript log

* Avoid appending to active transcript log

* Log install uninstall package identities

functions/public/Invoke-WPFRunspace.ps1

@@ -34,11 +34,11 @@ function Invoke-WPFRunspace {
     $script:powershell = [powershell]::Create()
 
     # Add Scriptblock and Arguments to runspace
-    $script:powershell.AddScript($ScriptBlock)
-    $script:powershell.AddArgument($ArgumentList)
+    [void]$script:powershell.AddScript($ScriptBlock)
+    [void]$script:powershell.AddArgument($ArgumentList)
 
     foreach ($parameter in $ParameterList) {
-        $script:powershell.AddParameter($parameter[0], $parameter[1])
+        [void]$script:powershell.AddParameter($parameter[0], $parameter[1])
     }
 
     $script:powershell.RunspacePool = $sync.runspace