[SWSS:portsorch] missing child_ports checking in addLagMember and removeLagMember when setting interface strip tag

[baorliu]

in addLagMember and removeLagMember, it needs to check if the interface has child port, besides current checking on lag.m_bridge_port_id.

The issue is seen when a LAG member is added after sub interface creating, the interface strip tag is not set as expected.
cause the member is not working for packet with vlan_id.

I will create a PR to fix it.

@@ -7031,12 +7035,15 @@ bool PortsOrch::addLagMember(Port &lag, Port &port, string member_status)
 
     m_portList[lag.m_alias] = lag;
 
-    if (lag.m_bridge_port_id > 0)
+    if ((lag.m_bridge_port_id > 0)||(!lag.m_child_ports.empty())) 
     {

@@ -7079,7 +7086,8 @@ bool PortsOrch::removeLagMember(Port &lag, Port &port)
     lag.m_members.erase(port.m_alias);
     m_portList[lag.m_alias] = lag;
 
-    if (lag.m_bridge_port_id > 0)
+    if ((lag.m_bridge_port_id > 0)||(!lag.m_child_ports.empty()))