Set segment pill button corner radius

[joannaquu]

Platforms Impacted

• iOS
• macOS

Description of changes

Currently, SegmentedControl sets the cornerRadius. On iOS, this trickles down to SegmentPillButton as well. This is not true on other platforms. To fix this, set the cornerRadius explicitly.

To avoid magic numbers, move SegmentedControl.Constants to SegmentedControlTokenSet and access the corner radius from there. While I'm here, remove selectionBarHeight since it's not being used anywhere.

Binary change

Total increase: 2,224 bytes
Total decrease: -1,600 bytes

File	Before	After	Delta
Total	30,917,640 bytes	30,918,264 bytes	⚠️ 624 bytes

Full breakdown

File	Before	After	Delta
SegmentedControlTokenSet.o	90,128 bytes	91,448 bytes	⚠️ 1,320 bytes
SegmentPillButton.o	90,648 bytes	91,552 bytes	⚠️ 904 bytes
FocusRingView.o	814,848 bytes	814,688 bytes	🎉 -160 bytes
__.SYMDEF	4,770,960 bytes	4,770,720 bytes	🎉 -240 bytes
SegmentedControl.o	333,384 bytes	332,184 bytes	🎉 -1,200 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

[laminesm]

Should we consider making this a constant token instead of using a magic number?