Handle XRC snapshots outside of grid detect plan

Our ispyb callback for XRC assumes that the snapshots have been taken during the grid detect plan. For VMXm, there is no grid detect - we'd like snapshots to be taken independently using the `oav_snapshot_plan`

We need to adjust the XRC ispyb_callback so that it can also handle the event where the `oav_snapshot_plan` has been ran. This will probably look very similar to `activity_gated_event` in `rotation/ispyb_callback`

## Acceptance Criteria
- XRC ispyb callbacks listen for the `oav_snapshot_plan` and deposit these snapshots to ispyb
- This callback knows whether it needs to listen for the `oav_snapshot_plan` OR the snapshots in `grid_detection_plan`