chore(rule-engine): more safe generate even_msg content

apps/emqx_rule_engine/src/emqx_rule_events.erl

@@ -191,12 +191,12 @@ eventmsg_connected(_ClientInfo = #{
                     clean_start := CleanStart,
                     proto_name := ProtoName,
                     proto_ver := ProtoVer,
-                    keepalive := Keepalive,
-                    connected_at := ConnectedAt,
-                    conn_props := ConnProps,
-                    receive_maximum := RcvMax,
-                    expiry_interval := ExpiryInterval
+                    connected_at := ConnectedAt
                    }) ->
+    Keepalive = maps:get(keepalive, ConnInfo, 0),
+    ConnProps = maps:get(conn_props, ConnInfo, #{}),
+    RcvMax = maps:get(receive_maximum, ConnInfo, 0),
+    ExpiryInterval = maps:get(expiry_interval, ConnInfo, 0),
     with_basic_columns('client.connected',
         #{clientid => ClientId,
           username => Username,