MsgFlo coordinator didn't stop participant when clearing and re-sending graph

Viewing MsgFlo in Flowhub live mode, switching to edit mode: as result we have two running instances of `msgflo-register-foreign` with same role:

```
├─702 node ./node_modules/.bin/msgflo-register-foreign participants/panel.yml --role weltenbaulab --forever=true
├─828 node ./node_modules/.bin/msgflo-register-foreign participants/panel.yml --role weltenbaulab --forever=true
```