[media-ui]Centralize volume button accessibility semantics in VolumeScreen

[dianastefan12]

WHAT

Centralize volume button accessibility semantics inside VolumeScreen by wrapping increaseIcon and decreaseIcon in containers with explicit button semantics (clearAndSetSemantics).

WHY

Screen readers (TalkBack) were not consistently announcing or triggering actions on the volume increase and decrease controls in VolumeScreen. Explicitly setting accessibility semantics (contentDescription, Role.Button, and onClick actions) directly on the volume button slots ensures reliable accessibility interaction across Wear OS devices.

HOW

• Wrapped the increaseIcon and decreaseIcon slots in Stepper inside Box layout containers.
• Applied Modifier.clearAndSetSemantics to the icon boxes to configure:
  • contentDescription mapped to string resources (horologist_volume_screen_volume_up_content_description and horologist_volume_screen_volume_down_content_description).
  • role = Role.Button to indicate button behavior to accessibility services.
  • onClick action handlers executing increaseVolume() and decreaseVolume().

Checklist 📋

• Add explicit visibility modifier and explicit return types for public declarations
• Run spotless check
• Run tests
• Update metalava's signature text files

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[dianastefan12]

@googlebot I signed it!

[yschimke]

Is this a Wear Compose bug? Should we fix there? or is there a tracking bug?

[kul3r4]

@dianastefan12 did you also ran the media sample to confirm behaviour when talk back is enabled?

[dianastefan12]

Is this a Wear Compose bug? Should we fix there? or is there a tracking bug?

Here is the bug: https://b.corp.google.com/issues/512233745

[dianastefan12]

@dianastefan12 did you also ran the media sample to confirm behaviour when talk back is enabled?

Tested manually:

Test Case 1: TalkBack Accessibility Focus & Role Announcement
Open the Volume Control Screen in the Media Controller.
Move TalkBack focus to the Volume Up (+) icon:
Expected Result: TalkBack announces "Increase Volume, Button" and displays the green TalkBack focus indicator rectangle around the icon container.
Move TalkBack focus to the Volume Down (-) icon:
Expected Result: TalkBack announces "Decrease volume, Button" and displays the green TalkBack focus indicator rectangle around the icon container.

Test Case 2: Double-Tap Interaction under TalkBack Focus
Place TalkBack focus on the Volume Up (+) button and double-tap on the button:
Expected Result: Volume increases by one step. TalkBack announces the updated volume percentage (e.g., "50 percent" via live region update).
Move TalkBack focus to the Volume Down (-) button and double-tap on the buttton:
Expected Result: Volume decreases by one step. TalkBack announces the updated volume percentage.