Telephony(MSIM): Modify Local Call Hold flow.

The present change contains below fixes.
1) While an active voice call exists on a subscription, follow
below order to update LCH state to RIL layer.

 - When user placed MO call on another subscription, update
   LCH on existing/active subscription before sending DIAL request.
 - When user answer MT call on another subscription, update
   LCH on existing subscription before sending ANSWER request. Also
   Set audio mode to incall immediately after accepting the call
   and not wait till call is reported as ACTIVE by RIL.
2) If there is a Network held call on one sub and MO/MT call gets
connected on other sub, move network held call to lch.

CRs-Fixed:571380
Change-Id: I6086998df637b071872868e55abe1c30006e7aba