[core] Make include_log_monitor configurable in the ray start command

[kevin85421]

Why are these changes needed?

In #48642, the user creates two Ray nodes in the local environment, causing both the head and worker nodes to launch a log monitor process. As a result, the logs are printed in the driver process twice.

This PR makes --include-log-monitor configurable, allowing users to launch a log monitor process only when starting the head node, preventing duplicate logs.

# test.py
import ray

@ray.remote
def foo():
    print('hello')


if __name__ == '__main__':
    ray.init()
    handle = foo.remote()
    ray.get(handle)

Related issue number

Closes #48642

Checks

• I've signed off every commit(by using the -s flag, i.e., git commit -s) in this PR.
• I've run scripts/format.sh to lint the changes in this PR.
• I've included any doc changes needed for https://docs.ray.io/en/master/.
  • I've added any new APIs to the API Reference. For example, if I added a
    method in Tune, I've added it in doc/source/tune/api/ under the
    corresponding .rst file.
• I've made sure the tests are passing. Note that there might be a few flaky tests, see the recent failures at https://flakey-tests.ray.io/
• Testing Strategy
  • Unit tests
  • Release tests
  • This PR is not tested :(

[MengjinYan]

I have a general question: Wondering should also add the logic where we automatically set the include_log_monitor to false when there is more than 1 log monitor is running on a physical host?

[kevin85421]

I have a general question: Wondering should also add the logic where we automatically set the include_log_monitor to false when there is more than 1 log monitor is running on a physical host?

I initially attempted to automatically detect this situation (PR: #48676). However, the log monitor is not the only issue when running multiple Ray nodes on a single physical host. Therefore, @rkooo567 suggested providing an option to disable the log monitor instead.