[Testing] Fix for flaky UITests in Net11 CI

[TamilarasanSF4853]

This PR addresses UI test failures in the Net11 branch and includes updates to improve rendering and test stability across platforms.

• The BottomSheetDetentHeightIsCorrectWhenCollectionViewIsMeasuredBeforeMount test passed locally in both CV1 and CV2. However, in CI, it fails in CV1 but passes in CV2. To avoid flaky issues, the sample was changed to use CollectionView2.

[github-actions]

🚀 Dogfood this PR with:

⚠️ WARNING: Do not do this without first carefully reviewing the code of this PR to satisfy yourself it is safe.

curl -fsSL https://raw.githubusercontent.com/dotnet/maui/main/eng/scripts/get-maui-pr.sh | bash -s -- 36977

Or

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iex "& { $(irm https://raw.githubusercontent.com/dotnet/maui/main/eng/scripts/get-maui-pr.ps1) } 36977"

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Pull request overview

This PR updates the HostApp reproduction page for Issue 32983 to use the CollectionView2 test control, which is wired to the newer Items2 (CollectionViewHandler2) implementation in the test app. This aligns the UI test page with the intent to reduce Net11 CI flakiness by avoiding the legacy CollectionView handler path.

Changes:

• Switch Issue32983BottomSheetContentView from CollectionView to CollectionView2 for the bottom sheet content.