IMS: Update EXTRA_ANSWERING_DROPS_FG_CALL while video state
changes during the call

-In DSDA, the extra EXTRA_ANSWERING_DROPS_FG_CALL is enabled or not
 after call arrives and will not be updated before call is answered.
 It will result in that getting incorrect EXTRA_ANSWERING_DROPS_FG_CALL
 when answering the incoming call because another call in other sub has
 changed between this call arrives and this call is answered.

-Update EXTRA_ANSWERING_DROPS_FG_CALL in ringing connection while
 video state in active call changes during the call.

Change-Id: I41d2054f7a49ef598086c8aea024d85e70bcca91
CRs-Fixed: 3248643
1 file changed