Removed gifsCard labs flag
Removed gifsCard labs flag

refs https://github.com/TryGhost/Admin/commit/cec3d91c5745ec71fbb99a70525f64bb56596007

- flag is no longer used by Admin

ErisDS/Ghost,e10/Ghost,TryGhost/Ghost,ErisDS/Ghost,e10/Ghost,TryGhost/Ghost,ErisDS/Ghost,TryGhost/Ghost