separate URL for WFC settings

we have @SystemAPI exposed in ImsMMTelManager#getVoWiFiModeSetting
and ImsMMTelManager#getVoWiFiRoamingModeSetting and vtEnabled.
We should expose @System URI allowing listeners to be notified
on settings changes.

Bug: 118631333
Test: telephony unit test
Change-Id: I6deeb8c030eb0d27f350355f86ef17bdab6152b8
Merged-in: I6deeb8c030eb0d27f350355f86ef17bdab6152b8
1 file changed