fix(input): detect value when it is zero
fix(input): detect value when it is zero

thanks @keithdmoore

fixes #8019

AbraaoAlves/ionic,AbraaoAlves/ionic,jhlee8804/ionic,manucorporat/ionic,AbraaoAlves/ionic,manucorporat/ionic,driftyco/ionic,joshesp/ionic,joshesp/ionic,brianespinosa/ionic2-sass,cambronjay/ionic,joshesp/ionic,TillaTheHun0/ionic,dennybiasiolli/ionic,jhlee8804/ionic,manucorporat/ionic,jhlee8804/ionic,driftyco/ionic,jhlee8804/ionic,alan-agius4/ionic,manucorporat/ionic,dennybiasiolli/ionic,dennybiasiolli/ionic,alan-agius4/ionic,cambronjay/ionic,alan-agius4/ionic,cambronjay/ionic,cambronjay/ionic,manucorporat/ionic,driftyco/ionic,AbraaoAlves/ionic,driftyco/ionic,dennybiasiolli/ionic,AbraaoAlves/ionic,TillaTheHun0/ionic,TillaTheHun0/ionic,alan-agius4/ionic,driftyco/ionic,cambronjay/ionic,TillaTheHun0/ionic,alan-agius4/ionic,joshesp/ionic,alan-agius4/ionic,dennybiasiolli/ionic,jhlee8804/ionic