Update accessoryCheckmarkColor on visionOS to be white

[joannaquu]

Platforms Impacted

• iOS
• visionOS
• macOS

Description of changes

On visionOS, accessoryCheckmarkColor is currently brandForeground1. It should be white.

Binary change

Total increase: 1,144 bytes
Total decrease: 0 bytes

File	Before	After	Delta
Total	31,358,040 bytes	31,359,184 bytes	⚠️ 1,144 bytes

Full breakdown

File	Before	After	Delta
TableViewCellTokenSet.o	125,040 bytes	126,032 bytes	⚠️ 992 bytes
__.SYMDEF	4,830,360 bytes	4,830,512 bytes	⚠️ 152 bytes

Verification

Visual Verification

Before	After

Pull request checklist

This PR has considered:

• Light and Dark appearances
• iOS supported versions (all major versions greater than or equal current target deployment version)
• VoiceOver and Keyboard Accessibility
• Internationalization and Right to Left layouts
• Different resolutions (1x, 2x, 3x)
• Size classes and window sizes (iPhone vs iPad, notched devices, multitasking, different window sizes, etc)
• iPad Pointer interaction
• SwiftUI consumption (validation or new demo scenarios needed)
• Objective-C exposure (provide it only if needed)

Microsoft Reviewers: Open in CodeFlow