Gets the current brightness of the platform whether it's light or dark mode.
Returns either Brightness.light or Brightness.dark to match whether device
is in normal or dark mode respectively.
Sets the light theme with type T. Note that if your device is in dark mode,
using setTheme will not do anything until your device is switched
to light mode.
Sets the light theme with type T. Note that if your device is in dark mode,
using setTheme will not do anything until your device is switched
to light mode.