Fix font for actionbar in device default

The font family was not being set on the action bar causing
it to revert to roboto. This simply overrides that to match the
light theme version (since they should use the same font).

Test: Manually observing title text in Settings > Accessibility >
      Text-to-speech output > cog icon
Bug: 129995075

Change-Id: Ic5415e3441a978e7af500549bfcca8083b704b39