fix entitlement schema

Author: yujonglee

supabase/migrations/20250101000005_stripe_fix_entitlement_unique.sql

@@ -0,0 +1,6 @@
+alter table "stripe"."active_entitlements"
+    drop constraint if exists "active_entitlements_lookup_key_key";
+
+alter table "stripe"."active_entitlements"
+    add constraint "active_entitlements_customer_lookup_key_key"
+    unique ("customer", "lookup_key");