chore: remove duplicate import line (#379)

Author: dandhlee

packages/google-cloud-datastore/google/cloud/datastore/entity.py

@@ -44,7 +44,6 @@ class Entity(dict):
 
         import uuid
 
-        from google.cloud import datastore
         from google.cloud import datastore
 
         unique = str(uuid.uuid4())[0:8]