Remove support for "areas_2" field

The Admin app was only using this temporarily and is now using the
"areas" field instead [1], so we can delete this one.

[1]: https://github.com/alphagov/notifications-admin/pull/4006

app/broadcast_message/broadcast_message_schema.py

@@ -14,7 +14,6 @@ create_broadcast_message_schema = {
         'starts_at': {'type': 'string', 'format': 'datetime'},
         'finishes_at': {'type': 'string', 'format': 'datetime'},
         'areas': {'type': 'object'},
-        'areas_2': {'type': 'object'},
         'content': {'type': 'string', 'minLength': 1},
         'reference': {'type': 'string', 'minLength': 1, 'maxLength': 255},
     },
@@ -42,7 +41,6 @@ update_broadcast_message_schema = {
         'starts_at': {'type': 'string', 'format': 'datetime'},
         'finishes_at': {'type': 'string', 'format': 'datetime'},
         'areas': {'type': 'object'},
-        'areas_2': {'type': 'object'},
     },
     'required': [],
     'additionalProperties': False

app/broadcast_message/rest.py

@@ -138,7 +138,7 @@ def create_broadcast_message(service_id):
         template_id=template_id,
         template_version=template.version if template else None,
         personalisation=personalisation,
-        areas=data.get("areas", data.get("areas_2", {})),  # TEMPORARY: while we repurpose "areas"
+        areas=data.get("areas", {}),
         status=BroadcastStatusType.DRAFT,
         starts_at=_parse_nullable_datetime(data.get('starts_at')),
         finishes_at=_parse_nullable_datetime(data.get('finishes_at')),
@@ -170,8 +170,7 @@ def update_broadcast_message(service_id, broadcast_message_id):
             status_code=400
         )
 
-    # TEMPORARY: while we repurpose "areas"
-    areas = data.get("areas", data.get("areas_2", {}))
+    areas = data.get("areas", {})
 
     if ('ids' in areas and 'simple_polygons' not in areas) or ('ids' not in areas and 'simple_polygons' in areas):
         raise InvalidRequest(

app/models.py

@@ -2353,10 +2353,7 @@ class BroadcastMessage(db.Model):
             'personalisation': self.personalisation if self.template else None,
             'content': self.content,
 
-            # TEMPORARY: switch to this so we can repurpose "areas"
-            'areas_2': areas,
             'areas': areas,
-
             'status': self.status,
 
             'starts_at': get_dt_string_or_none(self.starts_at),