fix(logging): combine newline-split stdout messages into one log entry (#9757)
* fix(logging): combine newline-split stdout messages into one log entry
* Refactor StdoutEventHandler buffering logic and null handling
* formatting
* Update packages/devtools_app/release_notes/NEXT_RELEASE_NOTES.md
Co-authored-by: Kenzie Davisson <43759233+kenzieschmoll@users.noreply.github.com>
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Co-authored-by: Kenzie Davisson <43759233+kenzieschmoll@users.noreply.github.com>