The check for whether we're at the bottom or not allowed for a
difference of 1 to account for fractional scroll values, but
allowed the difference of exactly 1 too, meaning we'd consider
the timeline to be at the bottom if you were scrolled up by exactly
a single pixel. If your scrolling was set up to be precise enough and
the event handlers fired fast enough that they'd evaluate each time
you scrolled up by a single pixel, it would reset you back to the bottom
each time and you'd never be able to scroll up.
Fixes https://github.com/vector-im/element-web/issues/18903
I'm not really sure how this is meant to work - and I'm not sure
how it was working before, but this is causing fairly bad infinite
loops if I start element with no homeserver connection. This is
a fairly crude fix, only thing I can think that would be better is
some awareness of when network requests were failing and intentionally
backing off.
Fixes https://github.com/vector-im/element-web/issues/18242
