Added basic support for Windows App Actions. (#39927)

## Summary of the Pull Request
Adds basic support for finding, listing, and executing Windows App
Actions on files found by the Microsoft.CmdPal.Ext.Indexer extension.

## PR Checklist

- [X] **Closes:** #39926
- [X] **Communication:** I've discussed this with core contributors
already. If work hasn't been agreed, this work might be rejected
- [ ] **Tests:** Added/updated and all pass
- [X] **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

## Detailed Description of the Pull Request / Additional comments
We also update cswin32 to stable version.

<!-- Describe how you validated the behavior. Add automated tests
wherever possible, but list manual validation steps taken as well -->
## Validation Steps Performed
Validated that it doesn't show on older versions of Windows (<26100
insiders) and that it does work on newer version that have the App
Actions runtime.

---------

Co-authored-by: Gordon Lam (SH) <yeelam@microsoft.com>
Co-authored-by: Mike Griese <migrie@microsoft.com>
Co-authored-by: Leilei Zhang <leilzh@microsoft.com>

src/modules/cmdpal/ext/Microsoft.CmdPal.Ext.WebSearch/Helpers/DefaultBrowserInfo.cs

@@ -3,6 +3,7 @@
 // See the LICENSE file in the project root for more information.
 
 using System;
+using System.Runtime.InteropServices;
 using System.Text;
 using System.Threading;
 using ManagedCommon;
@@ -188,17 +189,20 @@ public static class DefaultBrowserInfo
                 {
                     var buffer = stackalloc char[128];
                     var capacity = 128;
-                    void* reserved = null;
+                    var firstChar = str[0];
+                    var strPtr = &firstChar;
 
                     // S_OK == 0
-                    if (global::Windows.Win32.PInvoke.SHLoadIndirectString(
-                            str,
+                    fixed (char* pszSourceLocal = str)
+                    {
+                        if (global::Windows.Win32.PInvoke.SHLoadIndirectString(
+                            pszSourceLocal,
                             buffer,
                             (uint)capacity,
-                            ref reserved)
-                        == 0)
-                    {
-                        return new string(buffer);
+                            default) == 0)
+                        {
+                            return new string(buffer);
+                        }
                     }
                 }