fix migrations import errors

archivebox/core/migrations/0027_update_snapshot_ids.py

@@ -2,7 +2,6 @@
 
 from django.db import migrations
 
-from django.db import migrations
 from datetime import datetime
 from abid_utils.abid import ABID, abid_from_values, DEFAULT_ABID_URI_SALT
 

archivebox/core/migrations/0059_tag_id.py

@@ -1,8 +1,9 @@
 # Generated by Django 5.0.6 on 2024-08-20 03:33
 
+from datetime import datetime
 from django.db import migrations, models
-from abid_utils.models import ABID, abid_from_values
-
+from abid_utils.abid import abid_from_values
+from abid_utils.models import ABID
 
 def calculate_abid(self):
     """