Show empty view when there are no voicemails

When there are no voicemails to be shown, we show an empty view. This is done by hiding the recycler view and showing the empty view. Similarly when a voicemail is present, we hide the empty view and then show the recycler view.

Bug: 25661977
Test: Unit Tests
PiperOrigin-RevId: 187396952
Change-Id: Ifa718fb05c1be37aabdf4c91bc2c1653357565b2
4 files changed