ui/cocoa: Fix the leak of qemu_console_get_label

Signed-off-by: Akihiko Odaki <akihiko.odaki@gmail.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20220215080307.69550-14-f4bug@amsat.org
Message-Id: <20220213021329.2066-1-akihiko.odaki@gmail.com>
[PMD: Use g_autofree, suggested by Zoltan BALATON]
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>