Use elog to report unexpected action in handle_streamed_transaction().

An oversight in commit 216a784829.

Author: Masahiko Sawada
Reviewed-by: Kyotaro Horiguchi, Amit Kapila
Discussion: https://postgr.es/m/CAD21AoDDbM8_HJt-nMCvcjTK8K9hPzXWqJj7pyaUvR4mm_NrSg@mail.gmail.com

src/backend/replication/logical/worker.c

@@ -658,7 +658,7 @@ handle_streamed_transaction(LogicalRepMsgType action, StringInfo s)
 			return false;
 
 		default:
-			Assert(false);
+			elog(ERROR, "unexpected apply action: %d", (int) apply_action);
 			return false;		/* silence compiler warning */
 	}
 }