Fix GlobalActions sound panel iconography.

The priority and none icons were using old zen icons and did not
match up with the status bar iconography. We are now in sync. Also
aligning the prefix to match the other icons present in this dialog.
Lastly, creating new drawables for the two sound options so that
we don't clash designs with the Settings view, which also used the
same icons.

Change-Id: I0a0cee6c7f0f7b014a0b2cdd95b7f7e5cb8e5f38
Ticket: CYNGNOS-2172