Revert "test(firefox): Use a known good version"

This reverts commit 5736abd639c55b33b00e277ee358a22e93757f5e.
test(rxSortableColumn): Headless test experiment

On my machine I'm not getting any "more than one element found" for the
rxSortableColumn tests, but in headless environments it's almost
like...there's two sets of columns somehow? I'm not sure.

I've noticed that the first test doesn't seem to complain, but
afterwards, it starts to see multiple sets of columns. I have a
suspicion that there's some kind of odd behavior that happens after the
first interaction with the columns, so I'm skipping all tests before
these new ones I added.