Bug 1848096: Allow multi filebrowsers on one form

As we have 2 filebrowsers on the form using it's normal reply back
logic was not going to work.

Had to change it so that folder update updates the correct element

behatnotneeded

Change-Id: I24a1cdba65608a0328bd6db98840c62367975f1b
Signed-off-by: Robert Lyon <robertl@catalyst.net.nz>