De-couple data enabled from VT settings.

The existing KEY_IGNORE_DATA_ENABLED_CHANGED_FOR_VIDEO_CALLS has the impact
of decoupling whether VT is enabled from whether mobile data is enabled.
Making this TRUE by default.
Adding a new carrier config option to indicate whether VILTE data is metered.
This, coupled with KEY_IGNORE_DATA_ENABLED_CHANGED_FOR_VIDEO_CALLS allows
us to ensure that wifi video calls can be made, while still ensuring that
mobile data is not used for VT calls.
A carrier config update needs to be made for the few instances where
KEY_IGNORE_DATA_ENABLED_CHANGED_FOR_VIDEO_CALLS was set true to ensure
that KEY_VILTE_DATA_IS_METERED_BOOL is false in that case.

Test: Manual
Bug: 36900451
Change-Id: I037f8930901907b55e4245a655e0480668549185