Remove MASTER_MONO from replaced settings

Bug: 153940088
Test: build

In ag/11078633 we added logic for special-casing B&R of temporarily
replaced system settings. Remove Settings.System.MASTER_MONO from that list as
it won't be replaced anymore.

Change-Id: I27e519c58b9d621465c882d8ed2532bfda884d02
1 file changed