nxos_igmp_interface: argument_spec for oif_ps breaks when 'default' (#53136)

The `oif_ps` attr expects a list of dicts but it also supports keyword 'default'.
When the playbook specifies `oif_ps: default` the `nxos_igmp_interface` module fails:

```
"msg": "Elements value for option oif_ps is of type <type 'str'> and we were unable to convert to dict: dictionary requested, could not parse JSON or key=value"
```

This test used to work afaik so I believe `AnsibleModule` may have changed at some point to enforce strict type checking, causing this failure. I did not see another way to handle both list & str types for the same attr so I just set it to `raw`.

`nxos_igmp_interface/tests/common/sanity` now has 100% pass rate.

lib/ansible/modules/network/nxos/nxos_igmp_interface.py

@@ -367,7 +367,7 @@ def config_igmp_interface(delta, existing, existing_oif_prefix_source):
     def_vals = get_igmp_interface_defaults()
 
     for key, value in delta.items():
-        if key == 'oif_ps':
+        if key == 'oif_ps' and value != 'default':
             for each in value:
                 if each in existing_oif_prefix_source:
                     existing_oif_prefix_source.remove(each)
@@ -497,7 +497,7 @@ def main():
         oif_routemap=dict(required=False, type='str'),
         oif_prefix=dict(required=False, type='str', removed_in_version='2.10'),
         oif_source=dict(required=False, type='str', removed_in_version='2.10'),
-        oif_ps=dict(required=False, type='list', elements='dict'),
+        oif_ps=dict(required=False, type='raw'),
         restart=dict(type='bool', default=False),
         state=dict(choices=['present', 'absent', 'default'],
                    default='present')
@@ -592,7 +592,7 @@ def main():
     delta = dict(set(proposed.items()).difference(existing.items()))
 
     if oif_ps:
-        if oif_ps == ['default']:
+        if oif_ps == 'default':
             delta['oif_ps'] = []
         else:
             delta['oif_ps'] = oif_ps