[Bug]: file-input doesnt handle disabled state via reactive forms.

[emoralesb05]

Bug Report

File input needs to be able to be disabled when using reactive forms.

[n370]

I was recently finally able to reproduce the bug after following the discussion inside the merged PR referenced here. Actually it was the other way around, @emoralesb05 referenced this issue on that discussion but anyways I think I really get it now. I'm looking to find some time to open a PR with a fix within the next 24h but I'm new to Covalent and Angular Material so any suggestion, file or line reference pointing out where to look for things is very much appreciated. I'm though finding my way out alone so just let me know if that works for you. Thanks!