[Bugfix] Don't disable existing loggers

[a-ys]

One-liner that stops existing loggers from being disabled. By default, logging.dictConfig disables existing named loggers.

This bug only occurs when Ray is not installed (e.g. for AWS Neuron). This is because Ray adds this field to their logging configuration here.

FIX #5803

Code Example

import logging

logger = logging.getLogger("logger")

print(f"logger disabled: {logger.disabled}")
# Output: logger disabled: False

import vllm

print(f"logger disabled: {logger.disabled}")
# Before PR, if Ray is not installed:
# Output: logger disabled: True
# After PR:
# Output: logger disabled: False

[github-actions]

👋 Hi! Thank you for contributing to the vLLM project.
Just a reminder: PRs would not trigger full CI run by default. Instead, it would only run fastcheck CI which consists a small and essential subset of CI tests to quickly catch errors. You can run other CI tests on top of default ones by unblocking the steps in your fast-check build on Buildkite UI.

Once the PR is approved and ready to go, please make sure to run full CI as it is required to merge (or just use auto-merge).

To run full CI, you can do one of these:

• Comment /ready on the PR
• Add ready label to the PR
• Enable auto-merge.

🚀