Fix ios_l2_interface vlan bug CP in 2.6 (#44445)

* FIX ISSUE:#43878 when the vlans string have a final comma. (#43879)

(cherry picked from commit 401c45384e)

* Added changelog

changelogs/fragments/fix_ios_l2_interface_vlan.yaml

@@ -0,0 +1,3 @@
+---
+bugfixes:
+  - ios_l2_interface - fix bug when list of vlans ends with comma (https://github.com/ansible/ansible/pull/43879)

lib/ansible/modules/network/ios/ios_l2_interface.py

@@ -303,6 +303,7 @@ def vlan_range_to_list(vlans):
         for part in vlans.split(','):
             if part.lower() == 'none':
                 break
+            if part:
                 if '-' in part:
                     start, stop = (int(i) for i in part.split('-'))
                     result.extend(range(start, stop + 1))