one-time keys aren't reliably produced #1075

Describe the bug

Sable appears to stop providing the homeserver with new one-time keys, eventually leading to the user being unable to receive encrypted messages. Clearing the cache and reloading appears to cause Sable to continue producing one-time keys.

Reproduction

I have not figured out what causes Sable to stop producing new one-time keys, but once the issue starts the effects can be observed:

1. Send an encrypted message to the affected user's account
2. The affected user's one-time key count will decrement without being replenished

Expected behavior

The user's one-time keys will always be automatically replenished as they are used.

Platform and versions

1. OS: Linux Mint 22.3
2. Browser: Sable desktop app
3. Sable version: 1.19.4
4. Matrix homeserver: Continuwuity v26.6.1
This is my own information; other users I know who encounter this issue are using Sable 1.19.4 as a PWA or using the web app directly.

Additional context

Encryption appeared to work reliably prior to the Sable 1.19 release.