[Testing] The Windows WebView category is removed from CI because WebView2 is not connected in Appium. (#35335)

### Description of Changes

- Recently, the Appium driver has not been connecting properly to the
native WebView2 control on Windows. While running locally using Appium
Inspector with the WebView control, the inspector is unable to recognize
the WebView and displays an error.

- Due to this Appium driver issue, the WebView lane in CI takes a long
time to run (approximately 3 hours) and eventually gets cancelled. As a
temporary workaround, the WebView lane has been temporarily removed from
the Windows CI pipeline to allow the CI process to complete more
quickly.
<img width="649" height="294" alt="image"
src="https://github.com/user-attachments/assets/68df006b-56d6-4bfa-870a-a4184f5b18b7"
/>
<img width="576" height="430" alt="image"
src="https://github.com/user-attachments/assets/40c222e8-4935-450d-be7e-5ee9245e9eb1"
/>


**Issue:** #35334

Author: TamilarasanSF4853

eng/pipelines/common/ui-tests.yml

@@ -457,9 +457,12 @@ stages:
               - job: winui_ui_tests_${{ project.name }}
                 strategy:
                   matrix:
+                    # WebView is excluded on Windows: Appium driver cannot attach to WebView2
+                    # (appium/appium#22217 / dotnet/maui#35334). Remove this filter once fixed.
                     ${{ each categoryGroup in parameters.categoryGroupsToTest }}:
-                      ${{ categoryGroup }}:
-                        CATEGORYGROUP: ${{ categoryGroup }}
+                      ${{ if ne(categoryGroup, 'WebView') }}:
+                        ${{ categoryGroup }}:
+                          CATEGORYGROUP: ${{ categoryGroup }}
                 timeoutInMinutes: ${{ parameters.timeoutInMinutes }} # how long to run the job before automatically cancelling
                 workspace:
                   clean: all