[ci-scan-net11] Controls (API 30) CollectionView — VerifyHeader* tests time out on Android API 30 emulator (net11.0)

## Summary
CollectionView `VerifyHeader*` UI tests time out on Android API 30 emulator — recurring in `maui-pr-uitests` on `net11.0`.

## Build Information
- **Pipeline**: maui-pr-uitests (ID 313)
- **Build**: [1520373](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1520373)
- **Build ID**: 1520373
- **Branch**: net11.0
- **First seen**: 2026-07-07 (build 1496867)
- **Occurrences**: 2 in last 10 builds

## Affected Legs
- `Controls (API 30) CollectionView` — Android API 30 emulator — `VerifyHeader*` test group

## Error Message
```
Failed VerifyHeaderTemplateWhenGroupFooterTemplate [14 s]
Error Message:
System.TimeoutException : Timed out waiting for element...

Failed VerifyHeaderTemplateWhenGroupHeaderTemplate [15 s]
Error Message:
System.TimeoutException : Timed out waiting for element...

Failed VerifyHeaderStringWithItemsSourceObservableCollection5 [16 s]
Error Message:
System.TimeoutException : Timed out waiting for element...

(Also: VerifyHeaderViewWhen*, VerifyHeaderViewWith* — ~15+ tests total in the header test group)
```

## Recommended Action
1. Investigate CollectionView header rendering on Android API 30 emulator — the header element is not appearing within the timeout window.
2. Check `src/Controls/tests/TestCases.Shared.Tests/Tests/CollectionView/CollectionViewHeaderTests.cs` (or equivalent) for the `VerifyHeader*` tests.
3. Examine recent changes to `src/Controls/src/Core/Handlers/Items/Android/` that may affect header rendering on API 30 specifically.
4. The issue appeared on 2026-07-07 and recurred on 2026-07-22, suggesting an intermittent emulator responsiveness or layout timing regression on Android API 30 (not seen on other API levels in the same builds).

> Generated by [CI Failure Scanner (net11.0)](https://github.com/dotnet/maui/actions/runs/29922707151)

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> Generated by [CI Failure Scanner (net11.0)](https://github.com/dotnet/maui/actions/runs/29922707151) · 270.5 AIC · ⌖ 4.85 AIC · ⊞ 8.5K · [◷](https://github.com/search?q=repo%3Adotnet%2Fmaui+is%3Aissue+%22gh-aw-workflow-call-id%3A+dotnet%2Fmaui%2Fci-status-net11%22&type=issues)

Start with src/Controls/tests/TestCases.Shared.Tests/Tests/CollectionView/CollectionViewHeaderTests.cs and reproduce the VerifyHeader* failures on the Android API 30 emulator. Then inspect recent changes under src/Controls/src/Core/Handlers/Items/Android/ affecting header rendering. Done means the affected header tests no longer time out in the maui-pr-uitests CollectionView leg.

Written by the indexing model from the issue text.