## Description

This PR fixes `NavigationRail` hover position when using enlarged icons whose size is specified using `NavigationRailThemeData.selectedIconTheme` and `NavigationRailThemeData.unselectedIconTheme`.

## Related Issue

Fixes https://github.com/flutter/flutter/issues/133799.

## Tests

Adds 1 test, updates 1 test (to replace some magic numbers).