Format codebase after code generation in backend_addon not working

1.  Create and addon whith `uvx cookieplone backend_addon`
2. run `make format`
3. output:
```
==> Format codebase
Installed 1 package in 3ms
Found 6 errors (6 fixed, 0 remaining).
Installed 1 package in 5ms
5 files reformatted, 14 files left unchanged
Installed 6 packages in 32ms
```

5 files reformatted.