fix ipv5 mgmt address getter and tests

tests/01-smoke/01-basic-flow.robot

@@ -11,6 +11,8 @@ ${runtime}        docker
 # defaults to docker exec. Will be rewritten to containerd `ctr` if needed in "Define runtime exec" test
 ${runtime-cli-exec-cmd}    sudo docker exec
 ${bind-orig-path}    /tmp/clab-01-test.txt
+${n2-ipv4}        172.20.20.100/24
+${n2-ipv6}        2001:172:20:20::100/64
 
 *** Test Cases ***
 Deploy ${lab-name} lab
@@ -85,6 +87,16 @@ Verify port forwarding for node l2
     Should Be Equal As Integers    ${rc}    0
     Should Contain    ${output}    Thank you for using nginx
 
+Verify static mgmt addressing for l2
+    ${rc}    ${ipv4} =    Run And Return Rc And Output
+    ...    ${runtime-cli-exec-cmd} clab-2-linux-nodes-l2 ip -o -4 a sh eth0 | cut -d ' ' -f7
+    Log    ${ipv4}
+    Should Be Equal As Strings    ${ipv4}    ${n2-ipv4}
+    ${rc}    ${ipv6} =    Run And Return Rc And Output
+    ...    ${runtime-cli-exec-cmd} clab-2-linux-nodes-l2 ip -o -6 a sh eth0 | cut -d ' ' -f7 | head -1
+    Log    ${ipv6}
+    Should Be Equal As Strings    ${ipv6}    ${n2-ipv6}
+
 Destroy ${lab-name} lab
     ${rc}    ${output} =    Run And Return Rc And Output
     ...    sudo containerlab --runtime ${runtime} destroy -t ${CURDIR}/01-linux-nodes.clab.yml --cleanup

tests/01-smoke/01-linux-nodes.clab.yml

@@ -17,6 +17,8 @@ topology:
       image: nginx:stable-alpine
       ports:
         - 56180:80
+      mgmt_ipv4: 172.20.20.100
+      mgmt_ipv6: 2001:172:20:20::100
 
   links:
     - endpoints: ["l1:eth1", "l2:eth1"]

types/node_definition.go

@@ -111,7 +111,7 @@ func (n *NodeDefinition) GetMgmtIPv6() string {
 	if n == nil {
 		return ""
 	}
-	return n.MgmtIPv4
+	return n.MgmtIPv6
 }
 
 func (n *NodeDefinition) GetPublish() []string {