Held Conference call should not be automatically resumed

While removing call, if the forground call is in hold, then
CallsManager in Telecom is trying to resume the call.
foreground call should not be resumed when the disconnected
call was one of the conference call. So, other calls state
will remain same as before.

Test: manual - conference call scenarios
Bug: 34830478
Change-Id: I27a1d4fa09d4dd8e6dbb78d2fe60efe1b230e0e6