Provisioning: User with editor role can save provisioned dashboard in JSON Model

### What happened? A provisioned dashboard can be changed in the UI under Settings → JSON Model. ### What did you expect to happen? Not being able to save a provisioned dashboard if the user is not an administrator. ### Did this work before? I saw in https://github.com/grafana/grafana/issues/26620 and https://github.com/grafana/grafana/issues/44829 that this problem was mentioned in 2020 and 2022, but I do not know if it worked before, as I only just discovered this in my environment. ### How do we reproduce it? 1. In any provisioned dashboard, go to **Settings → JSON Model**. 2. Modify the JSON (something relevant, like the title). 3. Click **"Save changes"** ### Is the bug inside a dashboard panel? No ### Environment (with versions)? Grafana: 12.3.1 OS: Linux (Docker) Browser: Edge ### Grafana platform? Docker ### Datasource(s)? _No response_