Enhance app removal verification and error reporting (#735)

Tests/Wait-ForKeyPress.Tests.ps1

@@ -8,4 +8,14 @@ Describe 'Wait-ForKeyPress' {
 
         $LASTEXITCODE | Should -Be 0
     }
+
+    It 'uses the requested exit code' {
+        $scriptPath = Join-Path $PSScriptRoot '..\Scripts\CLI\Wait-ForKeyPress.ps1'
+        $command = "function Stop-Transcript {}; `$global:Silent = `$true; . '$scriptPath'; Wait-ForKeyPress -ExitCode 1"
+        $encodedCommand = [Convert]::ToBase64String([Text.Encoding]::Unicode.GetBytes($command))
+
+        & powershell.exe -NoProfile -EncodedCommand $encodedCommand
+
+        $LASTEXITCODE | Should -Be 1
+    }
 }