[ci-scan] Recurring MacCatalyst Label line-height visual baseline mismatch

## Summary
The MacCatalyst Label line-height visual test has failed in three of the last ten main builds with a snapshot mismatch.

## Build Information
- **Pipeline**: maui-pr-uitests
- **Build**: https://dev.azure.com/dnceng-public/public/_build/results?buildId=1574142
- **Build ID**: 1574142
- **Branch**: main
- **First seen**: 2026-08-21
- **Occurrences**: 3 in last 10 builds

## Affected Legs
- MacCatalyst UI tests / Mac

## Error Message
```
2026-08-30T14:17:40.9377100Z Failed VerifyLabelWithTextWhenLineHeight [50 s]
2026-08-30T14:17:40.9378650Z Snapshot different than baseline: VerifyLabelWithTextWhenLineHeight.png (2.40% difference)
```

## Recommended Action
Compare the current MacCatalyst snapshot with the approved baseline for `LabelFeatureTests.VerifyLabelWithTextWhenLineHeight`; investigate Label line-height measurement and update the baseline only if the rendering change is intentional.

Start with the maui-pr-uitests failure log and the LabelFeatureTests.VerifyLabelWithTextWhenLineHeight snapshot named in the report. Compare the current MacCatalyst image with its approved baseline, then confirm the baseline is updated only if the line-height rendering change is intentional.

Written by the indexing model from the issue text.