Reactions aren't rendered on refresh in E2EE rooms when "Show hidden events in timeline" labs option enabled

### Description

When the "Show hidden events in timeline" labs option is enabled, reactions aren't rendered in E2EE rooms upon initial refresh of riot-web.

### Steps to reproduce

1. React to a message in an E2EE room.
2. Refresh riot-web page in browser.
3. Reaction will not be rendered under the message reacted to.
4. Navigate to another room and then back again.
5. Reaction will now be rendered.

Logs being sent: no

### Version information

- **Platform**: riot-web

For the web app:

- **Browser**: qutebrowser (Chromium-like)
- **OS**: Void Linux
- **URL**: develop.element.io

Reproduce the issue in riot-web at develop.element.io with “Show hidden events in timeline” enabled, using an E2EE room and a reacted message. Compare the initial page refresh with navigating away and back, then trace the timeline reaction rendering and verify that reactions appear immediately after refresh.

Written by the indexing model from the issue text.