Improve readability of MasterRunner.client_listener #2120

Job	Run time
Always - Docker verify, push to tag 'master' if on master	0s
flake8	15s
lint_typecheck_webui	1m 20s
black	17s
mypy	20s
3.12	7m 21s
3.11	7m 11s
3.10	6m 55s
3.9	6m 56s
3.8	6m 53s
Tagged - Docker push to tag based on git tag. Also push 'latest' if on master	0s
PyPI - Publish prerelease on merge commit on master	0s
PyPI - Publish if this is a tagged commit	0s
	37m 28s

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