Fixes#21557-Handled dellos9_facts crash with IPV6 configs (#21652)

(cherry picked from commit cd662efd2b)

lib/ansible/modules/network/dellos9/dellos9_facts.py

@@ -309,6 +309,7 @@ class Interfaces(FactsBase):
 
     def populate_ipv6_interfaces(self, data):
         for key, value in data.items():
+            if key in self.facts['interfaces']:
                 self.facts['interfaces'][key]['ipv6'] = list()
                 addresses = re.findall(r'\s+(.+), subnet', value, re.M)
                 subnets = re.findall(r', subnet is (\S+)', value, re.M)