Correct naming issues with video calling carrier config items.

- Removed BOOL_ALLOW_VIDEO_PAUSE as it appears it was already added
as KEY_SUPPORT_PAUSE_IMS_VIDEO_CALLS_BOOL.
- Renamed BOOL_ALLOW_EMERGENCY_VIDEO_CALLS to KEY_ALLOW_EMERGENCY_VIDEO_CALLS_BOOL.

Bug: 27346047
Change-Id: I9f772e68ad9e78ce5a0419387c85a7f9630ecd5f