Just as we already call flatpak_disable_fancy_output() in
flatpak_option_context_parse() in case verbose output is enabled via CLI
options, disable fancy output in case verbose output was enabled via the
G_MESSAGES_DEBUG env var. Without this change, the result of doing e.g.
$ G_MESSAGES_DEBUG=OSTree flatpak install ...
is pretty useless and ugly, when the output isn't being redirected to a
file, since the debug messages are overwritten when we redraw to show
progress updates.
This makes the output of "flatpak list" a bit ugly when G_MESSAGES_DEBUG
is set, but it seems like a small price to pay.
784bc5566d