[FireAtlas] Possibility to update grid size once you are in the atlas

### What could be improved

Add the possibility to update grid size once you are in the atlas

### Why should this be improved

So that you don't have to recreate the atlas to set a new grid size

### Risks

Might be complicated if there already are selections in the atlas

### More information

_No response_

### Other

- [ ] Are you interested in working on a PR for this?