No warning before modifying a model that will break downstream dependencies

Nobody has claimed this yet.

### Describe the bug

If you make a model, make questions out of it and then modify the model, you don't get a warning if you're going to break questions that will use the model/field that you modify

### To Reproduce

1) create a model from the orders table
2) x-ray it, save the x-ray
3) modify the model now, remove the created at field, save
4) see that your saved dashboard from the x-ray broke (and most questions out of it, but you never got any warning

### Expected behavior

We should tell the user that it's going to break downstream dependencies (as we track these)

### Logs

NA

### Information about your Metabase installation

```JSON
v63
```

### Severity

P1

### Additional context

NA

Reproduce the issue by creating a model from the orders table, saving its x-ray, and removing the created-at field. Start by tracing the model modification flow and the existing downstream-dependency tracking described in the issue. Done means users are warned before a model change breaks saved dashboards or questions.

Written by the indexing model from the issue text.