[vlanmgr]Fix for STATE_DB port check logic (sonic-net#1980)

* Updated checks for PORT entry in STATE_DB in vlanmgrd additionally check for presence of "state" attribute. This is to add Vlanmgrd check similar to sonic-net#1936
Signed-off-by: Sudharsan Dhamal Gopalarathnam <sudharsand@nvidia.com>

cfgmgr/vlanmgr.cpp

@@ -7,6 +7,7 @@
 #include "tokenize.h"
 #include "shellcmd.h"
 #include "warm_restart.h"
+#include <swss/redisutility.h>
 
 using namespace std;
 using namespace swss;
@@ -461,6 +462,11 @@ bool VlanMgr::isMemberStateOk(const string &alias)
     }
     else if (m_statePortTable.get(alias, temp))
     {
+        auto state_opt = swss::fvsGetValue(temp, "state", true);
+        if (!state_opt)
+        {
+            return false;
+        }
         SWSS_LOG_DEBUG("%s is ready", alias.c_str());
         return true;
     }