Dry Run outputs don't aren't written to the log file

[mp3monster]

Bug Report

Describe the bug
Trying to capture the output of a dry_run to a log file - so we can automate a basic regression test results in no file. For example:
fluent-bit -vv -l ./test.txt --dry-run -c ./test.yaml

The console output reflects the expected output. We've tried to work around the issue by directing stdout and stderr to a shell, but we see the same problem.

We suspect that during dry run the log file isn't enabled, or it isn't being properly closed.

To Reproduce
With the following test.yaml run the command above:

pipeline:
  inputs:
    - name: dummy
      tag: dummy
      interval_sec: '1'
  outputs:
    - name: stdout
      match: '*'

Expected behavior
We'd expect the log file to contain either the error output from the dry run or the 'configuration test is successful' message to be written to the file

Your Environment

• Version used: Windows and WSL2 Ubuntu 22.04
• Configuration: basic
• Environment name and version (e.g. Kubernetes? What version?): dos batch window and bash on ubuntu
• Server type and version: X64
• Operating System and version: Windows 11 Pro & Ubuntu 22.04 (on WSL2)

Additional context
We're trying to implement automated tests to ensure configurations remain valid. This is to help test a .conf to .yaml converter tool.