Dash: Users can write to config despire permissions (OIDC tested)

Dashy is a self-hostable personal dashboard. Prior to 4.0.8, Dashy deployments using OIDC can allow unauthenticated users or non-admin authenticated users to write changes to the main config.yaml through the config-saving functionality despite configured permissions, allowing unauthorized modification of dashboard configuration and potential service disruption. This issue is fixed in version 4.0.8.