fix(lxc): panic when cloning a container with empty IP config (#2347)

Signed-off-by: Pavel Boldyrev <627562+bpg@users.noreply.github.com>

Author: bpg

proxmoxtf/resource/container/container.go

@@ -1234,6 +1234,10 @@ func containerCreateClone(ctx context.Context, d *schema.ResourceData, m interfa
 		initializationIPConfig := initializationBlock[mkInitializationIPConfig].([]interface{})
 
 		for _, c := range initializationIPConfig {
+			if c == nil {
+				continue
+			}
+
 			configBlock := c.(map[string]interface{})
 			ipv4 := configBlock[mkInitializationIPConfigIPv4].([]interface{})