Adding flag android.view.flags.use_refactored_round_scrollbar to trunk_staging.

This change was automatically created by advancing the Gantry workflow at:
https://releasetracker.partner.android.com/changes/9j9kbri000001?build_unique_id=android_platform_wear_frameworks
Do not edit this file manually or revert this change - use the Gantry workflow to manage the state of this flag.

Bug: 333417898
Change-Id: Ib3555b77f6d0481a812d1f4bf5e25164f5b7e5f2
Flag: android.view.flags.use_refactored_round_scrollbar
Ignore-AOSP-First: AConfig change for future AOSP release