tests: don't request gpio-mockup chips for the version string test
tests: don't request gpio-mockup chips for the version string test

Change the line sizes list into an empty array.

Signed-off-by: Bartosz Golaszewski <108de5fbc428215dc26df4468b48691526611148@gmail.com>

brgl/libgpiod,brgl/libgpiod,brgl/libgpiod,brgl/libgpiod