Tile Palette: Blurry selection icon and inconsistent padding in brush selection dropdown

Steps to reproduce:

1. Create a project using the Universal 2D template
2. Go to "Window" -> "2D" -> "Tile Palette"
3. In the "Tile Palette" window, find the "Default Brush" drop-down
4. Expand it and observe the UI

Actual results: Check mark is pixilated and blurry, top and bottom paddings are inconsistent

Expected results: Check mark should be bright and tidy, top and bottom paddings should be the same

Reproducible with versions: 6000.0.63f1, 6000.2.15f1, 6000.3.1f1, 6000.4.0a5, 6000.5.0a3

Tested on (OS): macOS - Tahoe 26.1