New Danger check to ensure a FF group is the same as the MR group label
Verification
| Case | Screenshot |
|---|---|
| Feature flag has no group and MR doesn't |  |
| Feature flag has no group but MR does |  |
Feature flag has no group: line and MR does |
 |
| Feature flag has a group but MR doesn't |  |
| Feature flag has a group which doesn't match the MR one |  |
Related to #299464 (closed).
Edited by Rémy Coutable