Grafana and telegraf config fixes

[macota]

• Grafana was failing with error

2024-06-11 10:16:27 Error: ✗ invalid setting [alerting].enabled
2024-06-11 10:17:27 logger=settings t=2024-06-11T08:17:27.755251893Z level=info msg="Starting Grafana" version=11.0.0 commit=83b9528bce85cf9371320f6d6e450916156da3f6 branch=v11.0.x compiled=2024-06-11T08:17:27Z
2024-06-11 10:17:27 logger=settings t=2024-06-11T08:17:27.755539908Z level=error msg="Option '[alerting].enabled' cannot be true. Legacy Alerting is removed. It is no longer deployed, enhanced, or supported. Delete '[alerting].enabled' and use '[unified_alerting].enabled' to enable Grafana Alerting. For more information, refer to the documentation on upgrading to Grafana Alerting (https://grafana.com/docs/grafana/v10.4/alerting/set-up/migrating-alerts)"

• Some mqtt files and configs snuck in from the other examples and was making telegraf fail

[macota]

remove grafana dashboard from mqtt example commit message should read "remove mqtt dashboard config from grafana"