Telecom:fix NPE problem to avoid telecom process crash.

   Firstly,the getConnectionServiceWrapper method in Call.java when
   mConnectionService or  mTransactionalService is null,we use this
   should make nonNull judgement as like  handleAddedCall method in
   ConnectionServiceFocusManager.java.

   Secondly,the releaseConnectionService method is called in
   handleReleasedFocusTimeout method in ConnectionServiceFocusManager.java.
   The parameter mCurrentFocus passed may be null sometime,we use this
   val before should make a nonNull judgement.

   Finally,we should make nonNull judgement for the connectionService
   and the return value of getConnectionServiceWrapper method.

Test: atest
Bug: 341659528
Change-Id: Id4cc6d3c9e32f157d795aed5cf4ff04c49d6efb6