feat(ActionBar): apply text color when largeTitletextAttribute is set on iOS (#6631)
feat(ActionBar): apply text color when largeTitletextAttribute is set on iOS (#6631)

* apply CSS text color when largeTitletextAttribute is set on iOS

* common logic improvment

NativeScript/NativeScript,NativeScript/NativeScript,NativeScript/NativeScript,NativeScript/NativeScript,NativeScript/NativeScript