Fix the non-working DND toggle

The pendingIntent of the DND toggle was set to immutable previously
which doesn't allow any modification. This CL fixes this by making it
mutable.

Fixes: 191865710
Test: Search "dnd" and make sure the toggle has effect upon modification
Change-Id: Iade256cee8885cb80ade5ca95cc50065c2a78da2
1 file changed