IMS : Dont treat Conference participants as individual calls

Fixes the logic which considers conference participants as individual
calls while trying to check for held calls

Change-Id: I5db3dcfb1fa21117b513bc30d94f81f5f2916643
CRs-Fixed: 2263985
Bug: 111866760
diff --git a/src/com/android/server/telecom/CallsManager.java b/src/com/android/server/telecom/CallsManager.java
index de22352..cda6054 100644
--- a/src/com/android/server/telecom/CallsManager.java
+++ b/src/com/android/server/telecom/CallsManager.java
@@ -2444,6 +2444,7 @@
     public Call getHeldCallByConnectionService(ConnectionServiceWrapper connSvr) {
         Optional<Call> heldCall = mCalls.stream()
                 .filter(call -> call.getConnectionService() == connSvr
+                        && call.getParentCall() == null
                         && call.getState() == CallState.ON_HOLD)
                 .findFirst();
         return heldCall.isPresent() ? heldCall.get() : null;