Enable cop Rails/TransactionExitStatement

See also gitlab-org/gitlab#410086

rubocop-rails.yml

@@ -196,6 +196,13 @@ Rails/SquishedSQLHeredocs:
 Rails/TimeZone:
   Enabled: false
 
+# Checks for the use of exit statements (namely return, break and throw) in
+# transactions. This is due to the eventual unexpected behavior when using
+# ActiveRecord >= 7, where transactions exited using these statements are being
+# rollbacked rather than committed (pre ActiveRecord 7 behavior).
+Rails/TransactionExitStatement:
+  Enabled: true
+
 # This cop checks for the use of old-style attribute validation macros.
 Rails/Validation:
   Enabled: true