[opampsupervisor] remove health check port

[TylerHelmuth]

Description

Removes the Agent's health_check_port feature. The opampsupervisor will no longer automatically start the collector with a healthcheck extension.

Testing

unit tests and e2e tests

[TylerHelmuth]

I want to test merging the extensions list from local config and remote config before we merge this.

[evan-bradley]

We have some logic to preserve lists under the services section of the config while merging the different sources in the Supervisor. Let me know if you see an issue with that during testing. I would have expected to see an E2E test covering this, but I don't; I'll look at adding one later.

Going forward, I think we should use the confmap.enableMergeAppendOption feature gate and pass the different config sources as separate files to the Collector and allow it to merge them.

[TylerHelmuth]

@evan-bradley Checkout how in the e2e test I had to update the healthcheck collector config to list the opamp extensions. I wasn't expecting to have to do that when using a local config. Based on my debugging today it was something with the bootstrap process.

I'll investigate in depth tomorrow.

[TylerHelmuth]

I confirmed that adding

extensions:
  health_check:
    endpoint: localhost:13133
service:
  extensions: [opamp,health_check]

to a local config causes the supervisor's collector not to start. Investigating why, but I suspect this is a local config but about adding extensions via a local config.

[TylerHelmuth]

I've confirmed this is an issue with local config including extensions: #39931