Improve error logging when TCP connections are prematurely closed by remote server

[DL6ER]

What does this implement/fix?

See title. This fixes an issue reported on Discourse (see below).

Related issue or feature (if applicable): Discourse topic

Pull request in docs with documentation (if applicable): N/A

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5. I have squashed any insignificant commits. (git rebase)

Checklist:

• [x] The code change is tested and works locally.
• [x] I based my code and PRs against the repositories developmental branch.
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[pralor-bot]

This pull request has been mentioned on Pi-hole Userspace. There might be relevant details there:

https://discourse.pi-hole.net/t/periodic-connection-errors-in-diagnostics-failed-to-send-tcp-read-write-to-127-0-0-1-5335/69961/6