Revert "Add WALLPAPER_PICKER_GRID_APPLY_BUTTON to SysUi Flags.kt"

Revert submission 24343660-picker-apply-button

Reason for revert: Build break on git_main branch on several targets

Reverted changes: /q/submissionid:24343660-picker-apply-button

Bug: 295257360
Change-Id: Ie634911352e4f5c37cc5f561fd30f81b49889f6e
2 files changed