Revert "Detour promoted notification demote button through Settings"

This reverts commit 49f4a8e7.

Reason for revert: With permission issue fixed, we can now directly modify through systemui UI.

Bug: 417258670
Flag:  com.android.systemui.permission_helper_ui_rich_ongoing
Test: manual
Change-Id: Ic9d0e091f4c4b4a22ef7a017160924f24a2209e0