Notification endpoint configurations are not updated unless notification rules change

The alerting UI suffers from a problem whereby changes to the configuration of a notification endpoint are not reflected in the running system unless a notification rule is also changed.

__Steps to reproduce:__

1. Alter a notification endpoint configuration of an established setup.

__Expected behavior:__

Configuration changes are reflected in the running system.

__Actual behavior:__

Changes do not take effect unless the notification rule configuration is also changed.

The issue names no files, tests, or entry points. Start by tracing how the alerting UI persists notification endpoint changes and how those changes reach the running system, then compare that path with notification rule updates. Done means an endpoint configuration change takes effect without changing a notification rule.

Written by the indexing model from the issue text.