Properly escape % in xml

Before we have this number of error
     50         id="StringFormatCount"
     95         id="StringFormatInvalid"

After we have this
     21         id="StringFormatInvalid"
     23         id="StringFormatCount"

Bug: 289445022
Test: m Bluetooth
Flag: Exempt lint
Change-Id: I6870f26b98e83cc19d8c59fc40bb15ea6cce4af4