CmdPal: Ignore failed package catalog completion events (#49887)

## Summary of the Pull Request

This PR prevents Command Palette from processing failed package
lifecycle operations as successful extension changes.

`PackageCatalog` can report an operation as complete while exposing the
failure through `ErrorCode`. Previously, `WinRTExtensionService` checked
only `IsComplete`, allowing failed installation, uninstallation, and
update operations to enter extension handling.

- Adds a shared `IsSuccessfulPackageOperation` check requiring both
    - the package operation to be complete, and
    - the projected `ErrorCode` to be null.
- The check is applied to catalog event:
    - `PackageInstalling`
    - `PackageUninstalling`
    - `PackageUpdating`


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## PR Checklist

- [x] Closes: #49886
<!-- - [ ] Closes: #yyy (add separate lines for additional resolved
issues) -->
- [ ] **Communication:** I've discussed this with core contributors
already. If the work hasn't been agreed, this work might be rejected
- [ ] **Tests:** Added/updated and all pass
- [ ] **Localization:** All end-user-facing strings can be localized
- [ ] **Dev docs:** Added/updated
- [ ] **New binaries:** Added on the required places
- [ ] [JSON for
signing](https://github.com/microsoft/PowerToys/blob/main/.pipelines/ESRPSigning_core.json)
for new binaries
- [ ] [WXS for
installer](https://github.com/microsoft/PowerToys/blob/main/installer/PowerToysSetup/Product.wxs)
for new binaries and localization folder
- [ ] [YML for CI
pipeline](https://github.com/microsoft/PowerToys/blob/main/.pipelines/ci/templates/build-powertoys-steps.yml)
for new test projects
- [ ] [YML for signed
pipeline](https://github.com/microsoft/PowerToys/blob/main/.pipelines/release.yml)
- [ ] **Documentation updated:** If checked, please file a pull request
on [our docs
repo](https://github.com/MicrosoftDocs/windows-uwp/tree/docs/hub/powertoys)
and link it here: #xxx

<!-- Provide a more detailed description of the PR, other things fixed,
or any additional comments/features here -->
## Detailed Description of the Pull Request / Additional comments

<!-- Describe how you validated the behavior. Add automated tests
wherever possible, but list manual validation steps taken as well -->
## Validation Steps Performed

src/modules/cmdpal/Microsoft.CmdPal.UI.ViewModels/Services/WinRTExtensionService.cs

@@ -152,9 +152,15 @@ public partial class WinRTExtensionService : IExtensionService, IDisposable
         }
     }
 
+    // C#/WinRT projects S_OK as null and every failed HRESULT as a non-null Exception.
+    internal static bool IsSuccessfulPackageOperation(bool isComplete, Exception? errorCode)
+    {
+        return isComplete && errorCode is null;
+    }
+
     private void Catalog_PackageInstalling(PackageCatalog sender, PackageInstallingEventArgs args)
     {
-        if (args.IsComplete)
+        if (IsSuccessfulPackageOperation(args.IsComplete, args.ErrorCode))
         {
             _ = HandlePackageInstalledAsync(args.Package);
         }
@@ -162,7 +168,7 @@ public partial class WinRTExtensionService : IExtensionService, IDisposable
 
     private void Catalog_PackageUninstalling(PackageCatalog sender, PackageUninstallingEventArgs args)
     {
-        if (args.IsComplete)
+        if (IsSuccessfulPackageOperation(args.IsComplete, args.ErrorCode))
         {
             _ = HandlePackageUninstalledAsync(args.Package);
         }
@@ -170,7 +176,7 @@ public partial class WinRTExtensionService : IExtensionService, IDisposable
 
     private void Catalog_PackageUpdating(PackageCatalog sender, PackageUpdatingEventArgs args)
     {
-        if (args.IsComplete)
+        if (IsSuccessfulPackageOperation(args.IsComplete, args.ErrorCode))
         {
             _ = HandlePackageUpdatedAsync(args.TargetPackage);
         }

src/modules/cmdpal/Tests/Microsoft.CmdPal.UI.ViewModels.UnitTests/WinRTExtensionServiceTests.cs

@@ -0,0 +1,33 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+using Microsoft.CmdPal.UI.ViewModels.Services;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+namespace Microsoft.CmdPal.UI.ViewModels.UnitTests;
+
+[TestClass]
+public class WinRTExtensionServiceTests
+{
+    [TestMethod]
+    public void IsSuccessfulCompletion_IncompleteOperation_ReturnsFalse()
+    {
+        Assert.IsFalse(WinRTExtensionService.IsSuccessfulPackageOperation(isComplete: false, errorCode: null));
+    }
+
+    [TestMethod]
+    public void IsSuccessfulCompletion_CompletedOperationWithoutError_ReturnsTrue()
+    {
+        Assert.IsTrue(WinRTExtensionService.IsSuccessfulPackageOperation(isComplete: true, errorCode: null));
+    }
+
+    [TestMethod]
+    public void IsSuccessfulCompletion_CompletedOperationWithAnyError_ReturnsFalse()
+    {
+        var error = new InvalidOperationException("Any projected package operation failure");
+
+        Assert.IsFalse(WinRTExtensionService.IsSuccessfulPackageOperation(isComplete: true, errorCode: error));
+    }
+}