No need to set a default tenancy and it prevents the creation of spot lcs (#31270)

The full traceback is:
Traceback (most recent call last):
  File "/tmp/ansible_82dk2ynr/ansible_module_ec2_lc.py", line 317, in create_launch_config
    connection.create_launch_configuration(**launch_config)
  File "/usr/lib/python3.6/site-packages/botocore/client.py", line 312, in _api_call
    return self._make_api_call(operation_name, kwargs)
  File "/usr/lib/python3.6/site-packages/botocore/client.py", line 601, in _make_api_call
    raise error_class(parsed_response, operation_name)
botocore.exceptions.ClientError: An error occurred (ValidationError) when calling the CreateLaunchConfiguration operation: Placement tenancy is not supported for spot instances.

fatal: [localhost]: FAILED! => {
    "changed": false, 
    "error": {
        "code": "ValidationError", 
        "message": "Placement tenancy is not supported for spot instances.", 
        "type": "Sender"
    }, 
    "failed": true,

lib/ansible/modules/cloud/amazon/ec2_lc.py

@@ -394,7 +394,7 @@ def main():
             classic_link_vpc_security_groups=dict(type='list'),
             classic_link_vpc_id=dict(),
             vpc_id=dict(),
-            placement_tenancy=dict(default='default', choices=['default', 'dedicated'])
+            placement_tenancy=dict(choices=['default', 'dedicated'])
         )
     )