fix ut issue and crash issue

source/dnode/mnode/impl/src/mndProfile.c

@@ -359,7 +359,6 @@ static int32_t mndProcessQueryHeartBeat(SMnode *pMnode, SRpcMsg *pMsg, SClientHb
         return -1;
       } else {
         mDebug("user:%s, conn:%u is freed and create a new conn:%u", connInfo.user, pBasic->connId, pConn->id);
-        pConn = mndAcquireConn(pMnode, pBasic->connId);
       }
     }
     

source/dnode/mnode/impl/test/profile/profile.cpp

@@ -88,7 +88,7 @@ TEST_F(MndTestProfile, 02_ConnectMsg_InvalidDB) {
 
 TEST_F(MndTestProfile, 03_ConnectMsg_Show) {
   test.SendShowReq(TSDB_MGMT_TABLE_CONNS, "connections", "");
-  EXPECT_EQ(test.GetShowRows(), 0);
+  EXPECT_EQ(test.GetShowRows(), 1);
 }
 
 TEST_F(MndTestProfile, 04_HeartBeatMsg) {