Fixes #20327: Device queries are now faster when including ConfidContexts

Move .distinct() from main queryset to tag subquery to eliminate
performance bottleneck when querying devices with config contexts.

The .distinct() call on the main device queryset was causing PostgreSQL
to sort all devices before pagination, resulting in 15x slower API
responses for large installations (10k+ devices, 100+ config contexts).

Moving .distinct() to the tag subquery eliminates duplicates at their
source (GenericForeignKey tag relationships) while preserving the fix
for issues #5314 and #5387 without impacting overall query performance.

netbox/extras/querysets.py

@@ -93,7 +93,7 @@ class ConfigContextModelQuerySet(RestrictedQuerySet):
                     _data=EmptyGroupByJSONBAgg('data', ordering=['weight', 'name'])
                 ).values("_data").order_by()
             )
-        ).distinct()
+        )
 
     def _get_config_context_filters(self):
         # Construct the set of Q objects for the specific object types
@@ -117,7 +117,7 @@ class ConfigContextModelQuerySet(RestrictedQuerySet):
                     ).values_list(
                         'tag_id',
                         flat=True
-                    )
+                    ).distinct()
                 )
             ) | Q(tags=None),
             is_active=True,