Avoid boxing for the txlogging task

[therustmonk]

📝 Summary

Improved how we launch the txlogging task.
Since monitor_tx_pool already returns a Future, we can simply reuse it.

💡 Motivation and Context

Reduce the number of boxes and closures to improve readability.

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✅ I have completed the following steps:

• Run make lint
• Run make test
• Added tests (if applicable)