Have the collector skip configurations without an uri

[Tdue21]

What would you like to be added:

I would like the health check collector service to skip configurations without an uri.

Why is this needed:

We are using the sample UI for the forseeable future. At some point we aim to build some kind of UI ourselves, but that is in the future.
I have finished a small project for pushing health checks via the IHealthCheckPublisher.

I have a process that receives these healthchecks and adds them to the database.
However, in order to show them, I have to create a record in the Configurations table and since this is push messages, the record does not have an uri.

This causes the collector to fail when it tries to collect from these configurations.
So, in the UI the state of the service changes between:

and

Depending on whether the collector or the push processor ran last.