[ci-scan] Android SafeAreaPerEdgeValidation ContentGrid height does not decrease

## Summary
`SafeAreaPerEdgeValidation` repeatedly reports that Android soft-input handling does not reduce the ContentGrid height.

## Build Information
- **Pipeline**: maui-pr-uitests
- **Build**: https://dev.azure.com/dnceng-public/public/_build/results?buildId=1554582
- **Build ID**: 1554582
- **Branch**: main
- **First seen**: 2026-08-10
- **Occurrences**: 3 in last 10 builds

## Affected Legs
- Controls SafeAreaEdges (API 36 Pixel 3 XL) / Android 36 / Mono

## Error Message
```
2026-08-15T21:57:51.5429596Z 1) ContentGrid height should be less when keyboard shows - MainGrid gets bottom padding from SoftInput
```

## Recommended Action
Inspect the Android safe-area and soft-input padding path used by `Issue28986.SafeAreaPerEdgeValidation`. Verify that the MainGrid receives bottom padding and that its measured height changes while the keyboard is visible.

Start with Issue28986.SafeAreaPerEdgeValidation and the Controls SafeAreaEdges leg in the maui-pr-uitests failure. Inspect the Android safe-area and soft-input padding path, then verify that MainGrid receives bottom padding and that ContentGrid's measured height decreases while the keyboard is visible.

Written by the indexing model from the issue text.