Encode + in WebUI commands so it doesn't get lost #868

Job	Run time
tests (ubuntu-latest, tests)	47s
build (ubuntu-latest, noradio)	1m 59s
build (ubuntu-latest, wifi)	2m 30s
tests (macos-latest, tests)	43s
build (ubuntu-latest, bt)	2m 8s
tests (windows-latest, tests_nosan)	1m 13s
build (macos-latest, noradio)	1m 46s
build (macos-latest, wifi)	1m 56s
build (macos-latest, bt)	1m 53s
build (windows-latest, noradio)	4m 44s
build (windows-latest, wifi)	4m 45s
build (windows-latest, bt)	4m 51s
	29m 15s

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