Ensure MERGE_COMPLETE connection event propagates for foreground call.

The connection event MERGE_COMPLETE was not propgating nor getting logged to the dumpsys as it was being invoked after the original calls had been diconnected in favor of the conference call and thus the listeners were removed at that point. This change ensures the MERGE_COMPLETE connection event properly propagates and logs to the dumpsys before the original foreground call is disconnected in favor of the conference call for IMS conferences.

Bug: 265187856
Test: Manually create an IMS conference call. Ensure MERGE_COMPLETE logs to the dumpsys for the original foreground call at time of merge.
Change-Id: I2426eddc88d49a9a6900ca65bb41d3295c86d772
diff --git a/src/com/android/services/telephony/ImsConferenceController.java b/src/com/android/services/telephony/ImsConferenceController.java
index 35b493a..fa2151b 100644
--- a/src/com/android/services/telephony/ImsConferenceController.java
+++ b/src/com/android/services/telephony/ImsConferenceController.java
@@ -431,6 +431,12 @@
             Log.w(this, "start new ImsConference - control should never come here");
             return;
         }
+
+        // Mark the foreground connection as MERGE_COMPLETE before it is disconnected as part of
+        // the IMS merge conference process:
+        connection.sendTelephonyConnectionEvent(
+                android.telecom.Connection.EVENT_MERGE_COMPLETE, null);
+
         // Make a clone of the connection which will become the Ims conference host connection.
         // This is necessary since the Connection Service does not support removing a connection
         // from Telecom.  Instead we create a new instance and remove the old one from telecom.