Do not try to force options to be strings
The may also be arrays, for instance
Trying to install qt5/qwebengine in a local craft, I got:
ERROR: Invalid command line parameter '['--webengine-pulseaudio=no', '--webengine-icu=system', '--webengine-jumbo-build=4']'.
Not sure why that is surfacing, now (did something set a default featureArguments option key, before?), but at any rate, converting all options to string does not look correct.