Fix duplicate key on SQLite (#4038)

* Fix duplicate key on SQLite

* Update migration

src/pretix/base/migrations/0260_alter_reusablemedium_index_together.py

@@ -0,0 +1,17 @@
+# Generated by Django 4.2.10 on 2024-04-02 15:16
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("pretixbase", "0259_team_require_2fa"),
+    ]
+
+    operations = [
+        migrations.AlterIndexTogether(
+            name="reusablemedium",
+            index_together=set(),
+        ),
+    ]

src/pretix/base/models/media.py

@@ -122,7 +122,6 @@ class ReusableMedium(LoggedModel):
     class Meta:
         unique_together = (("identifier", "type", "organizer"),)
         indexes = [
-            models.Index(fields=("identifier", "type", "organizer")),
             models.Index(fields=("updated", "id")),
         ]
         ordering = "identifier", "type", "organizer"