Refactor ExileTransferInstance messages for clarity and consistency

Updated the ExileTransferInstance message structure by renaming and reorganizing nested messages. Changed 'Call' to 'SourceCall' and 'DestinationCall', 'Agent' to 'DestinationAgent', and 'Phone' to 'DestinationPhoneNumber' for improved clarity. This enhances the overall readability and maintainability of the proto definitions.

Author: namtzigla

tcnapi/exile/gate/v2/entities.proto

@@ -169,28 +169,34 @@ message ExileTransferInstance {
   int64 pending_duration_microseconds = 26;
 
   message Source {
-    Call call = 1;
-    Agent agent = 2;
+    SourceCall call = 1;
+    message SourceCall {
+      string partner_agent_id = 1;
+      string user_id = 2;
+      string call_type = 3;
+      int64 conversation_id = 4;
+      string session_id = 5;
+    }
   }
   message Destination {
     oneof entity {
-      Call call = 1;
-      Agent agent = 2;
-      Phone phone = 3;
+      DestinationCall call = 1;
+      DestinationAgent agent = 2;
+      DestinationPhoneNumber phone = 3;
     }
     map<string, bool> skills = 7;
   }
-  message Call {
+  message DestinationCall {
     int64 call_sid = 1;
     string call_type = 2;
     int64 conversation_id = 3;
   }
-  message Agent {
+  message DestinationAgent {
     int64 session_sid = 1;
     string partner_agent_id = 2;
     string user_id = 3;
   }
-  message Phone {
+  message DestinationPhoneNumber {
     string phone_number = 1;
   }
   enum TransferType {