[INLONG-10191][Agent] Delete the useless code related to 8008 listen port

[justinwwhuang]

Fixes #10191

Motivation

The agent does not listen to the port, and the relevant code is useless

Modifications

Delete useless code

Verifying this change

(Please pick either of the following options)

• This change is a trivial rework/code cleanup without any test coverage.

• This change is already covered by existing tests, such as:
  (please describe tests)

• This change added tests and can be verified as follows:

  (example:)

  • Added integration tests for end-to-end deployment with large payloads (10MB)
  • Extended integration test for recovery after broker failure

Documentation

No doc needed

[dockerzhang]

please remove https://github.com/apache/inlong/blob/master/docker/docker-compose/docker-compose.yml#L102-L103 and https://github.com/apache/inlong/blob/master/inlong-agent/agent-docker/Dockerfile#L30

[justinwwhuang]

please remove https://github.com/apache/inlong/blob/master/docker/docker-compose/docker-compose.yml#L102-L103 and https://github.com/apache/inlong/blob/master/inlong-agent/agent-docker/Dockerfile#L30

done

[EMsnap]

public static final String AGENT_ENABLE_HTTP = "agent.http.enable";
public static final boolean DEFAULT_AGENT_ENABLE_HTTP = false; these codes should also be deleted

[EMsnap]

Please update https://inlong.apache.org/docs/next/modules/agent/configure

[dockerzhang]

Please update https://inlong.apache.org/docs/next/modules/agent/configure

updated in apache/inlong-website#955