Cannot set Query Variable with Cloud Logging data source

When we try to set the Logging scope via a Query variable we only see "Loading...". The plugin itself works fine and I see all logs, but I cannot use it as Variable and this currently makes it impossible to set a projectID in our dashboard.

Start by reproducing the issue with the Cloud Logging data source used as a Grafana Query variable, then compare its variable-loading path with the working log view. Trace the query-variable handling from the plugin entry point and verify that a projectID can be selected and resolved instead of remaining at “Loading...”.

Written by the indexing model from the issue text.