grafana admin: editing data source field did not have any effect

Created by: uwedeportivo

seen at a customer:

• 3.12.7
• k8s on gke

Steps to reproduce:

1. port-forward grafana (to avoid the csrf token issue, we will be doing put requests)
2. log into grafana as admin (if initial login it's admin/admin)
3. go to data sources, find prometheus and change the url value

Expected behavior:

new value should be saved and have an effect (either fixing the data source problem or if the edit is to a wrong url, breaking the data flow

Actual behavior:

editing the value had no visible effect

suspicion: seems like grafana is in read-only mode even for admins

we should reproduce locally and try other edits as well