set migration as dangerous

Author: mdtro

src/sentry/migrations/0631_apitoken_backfill_last_chars.py

@@ -27,7 +27,7 @@ class Migration(CheckedMigration):
     # - Adding indexes to large tables. Since this can take a long time, we'd generally prefer to
     #   have ops run this and not block the deploy. Note that while adding an index is a schema
     #   change, it's completely safe to run the operation after the code has deployed.
-    is_dangerous = False
+    is_dangerous = True
 
     dependencies = [
         ("sentry", "0630_better_monitor_latest_index"),