ms-appx: profile icons don't show in taskbar jump list when installed in portable mode

### Windows Terminal version

1.22.250204002

### Windows build number

10.0.19045.0

### Other Software

_No response_

### Steps to reproduce

Install in portable mode, pin to task bar, right-click.

(Note: I copied my settings .json files from an older non-portable install, so the existing profiles used ms-appx URLs.)

### Expected Behavior

Jump list should show all profile icons, including built-in ms-appx: ones.

### Actual Behavior

Only profile icons that are .exe file paths or https URLs work: ms-appx: URLs or paths/file: URLS for ico/png images do not.

To get profile icons working again, I ended up using https links to e.g. https://raw.githubusercontent.com/microsoft/terminal/refs/heads/main/src/cascadia/CascadiaPackage/ProfileIcons/%7B0caa0dad-35be-5f56-a8ff-afceeeaa6101%7D.scale-200.png in place of the corresponding ms-appx URL. (This is probably not a great idea but it works as a workaround.)

Start by reproducing the portable-mode installation, pinning Windows Terminal, and opening the taskbar jump list with profiles using ms-appx: icons. Trace the jump-list profile icon handling and compare it with the working .exe and https cases; done means built-in ms-appx: profile icons appear alongside the other profile icons.

Written by the indexing model from the issue text.