Crash using VoiceOver while swiping through messages

Reported by @marcozehe:matrix.org in #a11y:matrix.org:

Hi! I encountered two crashes earlier today when reading channel backlog. The steps, roughly, were:

1. With VoiceOver on on iOS, open Riot, and open a channel.

2. Find the item that said "jump to first unread message" and double-tap.

3. Swipe right continuously, through the messages.

4. At some point near the end of the backlog, like the second or third-to-last message or so, I suddenly hear a bump sound as if there are no more items to go, and Riot closes. On next launch, I get the Crash dialog and am prompted to add a comment. I added a comment in both instances and included my Matrix username, complete with the at and colon signs.

Hope these help!

Crash logs are linked.

Start by reviewing the linked crash logs and reproducing the reported VoiceOver flow on iOS: open a channel, jump to the first unread message, then swipe through the backlog. Trace the crash near the end of the messages and confirm that continuous swiping no longer closes Riot.

Written by the indexing model from the issue text.