Notify the developer when their local snap has been reinstalled

We currently automatically re-install local snaps, this isn't necessarily clear to developers. We should emit a browser notification whenever a `local:` snap is reinstalled. The `SnapController` already emits an event in this case, so we just need to listen for that and emit a browser notification as appropriate.

Start by locating the SnapController event emitted when a local: snap is reinstalled and find where browser notifications are handled. Listen for that event and verify that a browser notification appears after a local snap reinstall, without notifying for other snap types.

Written by the indexing model from the issue text.