fix: mobile ui-tests not working (backport #644)

[mergify]

This is an automatic backport of pull request #644 done by Mergify.
Cherry-pick of 4b5ce43 has failed:

On branch mergify/bp/legacy/3x/pr-644
Your branch is up to date with 'origin/legacy/3x'.

You are currently cherry-picking commit 4b5ce43.
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Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	deleted by us:   samples/Uno.Toolkit.Samples/Uno.Toolkit.Samples.Mobile/Android/MainActivity.Android.cs
	deleted by us:   samples/Uno.Toolkit.Samples/Uno.Toolkit.Samples.Mobile/Uno.Toolkit.Samples.Mobile.csproj
	deleted by us:   samples/Uno.Toolkit.WinUI.Samples/Uno.Toolkit.WinUI.Samples.Mobile/Android/MainActivity.Android.cs
	deleted by us:   samples/Uno.Toolkit.WinUI.Samples/Uno.Toolkit.WinUI.Samples.Mobile/Uno.Toolkit.WinUI.Samples.Mobile.csproj

no changes added to commit (use "git add" and/or "git commit -a")

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/github/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

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[Xiaoy312]

uno5.0-specific fixes
should not be backported