Fix cursor on click inputs and their descendants

The cursor in click inputs is shown as a pointer to convey that it can
be interacted with. However, in those click inputs that can have
descendants, like buttons, the descendants may not inherit the cursor
from it (for example, a "strong" element would, but a "span" element
would not), which causes a pointer cursor to be shown on some areas of
the button and a different one to be shown on other areas. To prevent
that now all the descendants of click inputs that can have descendants
use a pointer cursor.

On the other hand, if a click input is disabled it can not be interacted
with it, so now disabled click inputs as well as their descendants show
a default cursor instead of a pointer cursor in that case.

Signed-off-by: Daniel Calviño Sánchez <danxuliu@gmail.com>