Fix 403 error by using the existing, custom, HawkAuth class (#1001)

The addition of the payload to the GET request was causing the API to return a 403 error. However, removing the payload caused an exception from the `requests_hawk` package, requiring a payload when `always_hash_content=True`. Instead, we were able to resolve the issue by using the custom HawkAuth class, which is also used elsewhere in the EMT application.

app/enquiries/common/datahub_utils.py

@@ -6,11 +6,11 @@
 from datetime import date
 from django.conf import settings
 from django.forms.models import model_to_dict
-from requests_hawk import HawkAuth
 
 import app.enquiries.ref_data as ref_data
 from app.enquiries.utils import get_oauth_payload
 from app.enquiries.common.cache import cached_requests
+from app.enquiries.common.hawk import HawkAuth
 
 logger = logging.getLogger(__name__)
 
@@ -101,12 +101,9 @@ def fetch_metadata(name):
         response = cached_requests.get(
             url,
             auth=HawkAuth(
-                id=settings.DATA_HUB_ENQUIRY_MGMT_HAWK_ID,
-                key=settings.DATA_HUB_ENQUIRY_MGMT_HAWK_SECRET_KEY,
+                api_id=settings.DATA_HUB_ENQUIRY_MGMT_HAWK_ID,
+                api_key=settings.DATA_HUB_ENQUIRY_MGMT_HAWK_SECRET_KEY,
             ),
-            # Add dummy data to avoid error: MissingContent payload content and/or
-            # content_type cannot be empty when always_hash_content is True
-            data={"data": name},
             timeout=10,
         )
         response.raise_for_status()