Enable PDF files in preview pane (#9088)

## Summary of the Pull Request
This PR enables user to preview PDF files in the Explorer preview pane
and in Outlook. 

**What is this about:**
Windows does not support out of the box experience for previewing PDF
files in the preview pane. Users need to install third-party software
like Adobe Acrobat reader. The PdfPreviewHandler module enbales the user
to preview PDF files.

**How does someone test / validate:** 
Run the installer, open Explorer and select a PDF file, enable the
preview pane. Maybe need to remove third-party PDF software.

## Quality Checklist

- [X] **Linked issue:** #3548
- [ ] **Communication:** I've discussed this with core contributors in the issue. 
- [X] **Tests:** Added/updated and all pass
- [X] **Installer:** Added/updated and all pass
- [X] **Localization:** All end user facing strings can be localized
- [ ] **Docs:** Added/ updated
- [x] **Binaries:** Any new files are added to WXS / YML
   - [ ] No new binaries
   - [x] YML for signing
   - [x] WXS for installer

.pipelines/ci/templates/build-powertoys-steps.yml

@@ -122,6 +122,8 @@ steps:
     testAssemblyVer2: |
       **\UnitTests-SvgThumbnailProvider.dll
       **\Microsoft.PowerToys.Settings.UI.UnitTests.dll
+      **\UnitTests-MarkdownPreviewHandler.dll
+      **\UnitTests-PdfPreviewHandler.dll
       **\UnitTests-SvgPreviewHandler.dll
       **\UnitTests-PreviewHandlerCommon.dll
       **\PreviewPaneUnitTests.dll

.pipelines/pipeline.user.windows.yml

@@ -108,6 +108,8 @@ build:
             - 'modules\FileExplorerPreview\ManagedTelemetry.dll'
             - 'modules\FileExplorerPreview\MarkdownPreviewHandler.dll'
             - 'modules\FileExplorerPreview\MarkdownPreviewHandler.comhost.dll'
+            - 'modules\FileExplorerPreview\PdfPreviewHandler.dll'
+            - 'modules\FileExplorerPreview\PdfPreviewHandler.comhost.dll'
             - 'modules\FileExplorerPreview\powerpreview.dll'
             - 'modules\FileExplorerPreview\PreviewHandlerCommon.dll'
             - 'modules\FileExplorerPreview\SvgPreviewHandler.dll'