Fix potential crash for accessing models.
Fix potential crash for accessing models.

BaseModelsViewAdapter's GetModel method didn't take into account the
fact that when the IModelsView is loading, it should not crash when the
user requests a model at the very last position. Instead it should just
return null.

eatskolnikov/mobile,peeedge/mobile,ZhangLeiCharles/mobile,eatskolnikov/mobile,ZhangLeiCharles/mobile,peeedge/mobile,masterrr/mobile,masterrr/mobile,eatskolnikov/mobile