[minor] Improve logging for multiprocesses (#5004)
**Why?**
1. When the launcher starts multi-processes, there is no logs to show
what cmd each process is running
2. A small typo
**What?**
add logs to reflect what each process is doing
**Testing**
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Signed-off-by: byhsu <byhsu@linkedin.com>
Co-authored-by: byhsu <byhsu@linkedin.com>
