IMS-VT: Fix add call option missing issue after ending VT call.
Some operators disable adding another call when VT call is ongoing.
Currently there is an issue that add call option is not enabled for
active volte call when the held vt call is ended.
Fix this by refreshing disable add call extra for connection whenever
another connection disconnects.
Also check for background call and ringing calls when there is no
foreground call while deciding whether to disable add call option.
Change-Id: I42a127f6866ea5c9c31b4a697f52bacc8fee6bbe
CRs-Fixed: 2003983
2 files changed