fix: newlines for messages in log tail

[clumsy]

log shows lines separated by newlines correctly, but log -t has all lines jumbled up.

Test plan:
[x] added unit test

[clumsy]

A small but impactful quality of life fix for your consideration @kiukchung, @tonykao8080 @d4l3k @andywag

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.76%. Comparing base (c9b3dde) to head (a82cdf8).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1178      +/-   ##
==========================================
+ Coverage   91.72%   91.76%   +0.04%     
==========================================
  Files          86       86              
  Lines        6668     6668              
==========================================
+ Hits         6116     6119       +3     
+ Misses        552      549       -3     

Flag	Coverage Δ
unittests	91.76% <100.00%> (+0.04%)	⬆️

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[clumsy]

Please check the new version @kiukchung

[meta-codesync]

@kiukchung has imported this pull request. If you are a Meta employee, you can view this in D89891707.

[clumsy]

Thanks for checking @kiukchung, should I squash and merge now? (and for the future PRs)

[kiukchung]

Please check the new version @kiukchung

done!