"ALL"/"NONE" override toggle text is nearly invisible in Light theme for Volume Profile overrides (Tonemapping, Bloom, Motion Blur, etc.)

Steps to reproduce:

1. Create a Universal 2D project
2. Set Editor theme to Light (Preferences > General > Editor Theme)
3. In the Hierarchy, right-click > Volume > Global Volume 
4. Select the new GameObject
5. In the Inspector, next to the Volume component's "Profile" field, click "New" to create and assign a new Volume Profile
6. Click "Add Override" at the bottom of the Volume component, and add "Tonemapping" from the list
7. Click "Add Override" again and add "Bloom"
8. Click "Add Override" again and add "Motion Blur"
9. For each added override section (Tonemapping, Bloom, Motion Blur), observe the "ALL" / "NONE" toggle text at the top of that section
10. Compare against the same UI in Dark theme (Preferences > General > Editor Theme > Dark)

Actual results: In the Light theme, the "ALL" and "NONE" text is rendered in a very pale gray, nearly the same shade as its background - extremely low contrast, hard to read. In the Dark theme, the same text is clearly legible

Expected results: "ALL"/"NONE" text should have sufficient contrast against its background in Light theme, consistent with Dark theme and with the rest of the Editor's text

Reproducible with versions: 6000.5.7f1, 6000.6.0b8, 6000.7.0a5

Tested on (OS): MacBook Pro - Tahoe 26.6.1