Fix thumbnail caption of Image Resizer in Alt-Tab / Windows-Tab screens

### Description of the new feature / enhancement

Since moving to WinUI 3 (I guess), the thumbnail caption of Image Resizer is "WinUI Desktop" in the Alt-Tab or Windows-Tab screen. It should be "Image Resize" as it is for the window title.

### Scenario when this would be used?

Whenever a user goes to the Alt-Tab or Windows-Tab screen.

### Supporting information

_No response_

Start by locating the Image Resizer WinUI 3 window and the metadata used for its Alt-Tab and Windows-Tab thumbnails. Compare that caption with the existing window title; done means both task-switcher screens display "Image Resize" instead of "WinUI Desktop".

Written by the indexing model from the issue text.