## Update `AlertDialog` Documentation for Material 3 Defaults

This pull request updates the documentation for `AlertDialog` to accurately reflect the default text styles (`titleTextStyle` and `contentTextStyle`) when using Material 3.
Previously, the documentation suggested default styles (`TextTheme.titleLarge` for titles and `TextTheme.titleMedium` for content) that do not align with Material 3 implementation, which uses `TextTheme.headlineSmall` and `TextTheme.bodyMedium` respectively.

Fixes #144489