fix(input): don't allow focus when disabled is set

[brandyscarney]

Adds the disabled attribute to the parent input/textarea, also fixes
where disabled textareas were focusable regardless of where disabled
was set.

Testing this:

• Use http://localhost:8000/dist/e2e/input/form-inputs/
• There are two disabled inputs via formControl under the "Form w/ disabled inputs" header
• There are two disabled via attribute (one toggle) at the bottom

fixes #10155

[brandyscarney]

This also fixes where item wasn't getting .item-input-disabled like it should.

[jgw96]

LGTM on both Android and iOS