src/tests: Delete G_MESSAGES_DEBUG in desktop-testing for gsettings
src/tests: Delete G_MESSAGES_DEBUG in desktop-testing for gsettings

G_MESSAGES_DEBUG message could be appended to the output of gsettings
command and it's not useful to check the output.

ibus/ibus,fujiwarat/ibus,ibus/ibus,fujiwarat/ibus,fujiwarat/ibus,fujiwarat/ibus,ibus/ibus,ibus/ibus