[WIP] Allow looping uart streamed gcode #764

Job	Run time
build (ubuntu-latest, noradio)	1m 59s
build (ubuntu-latest, wifi)	2m 10s
tests (ubuntu-latest, tests)	30s
build (ubuntu-latest, bt)	2m 2s
tests (macos-latest, tests)	31s
build (macos-latest, noradio)	1m 37s
tests (windows-latest, tests_nosan)	1m 16s
build (macos-latest, wifi)	2m 4s
build (macos-latest, bt)	2m 0s
build (windows-latest, noradio)	4m 19s
build (windows-latest, wifi)	4m 52s
build (windows-latest, bt)	4m 46s
	28m 6s

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