Add Show Hidden Events In Timeline option

### Your use case

#### What would you like to do?
View hidden events in timeline, such as m.reaction events and non-standard events.

#### Why would you like to do it?
Allows me to see when someone reacts to a message off-screen. Allows showing who reacted to a message when screenshotting the timeline. Allows seeing non-standard events that people send, which is important for room moderation in case someone spams them.

#### How would you like to achieve it?
Add the "Show Hidden Events In Timeline" option to Element X

### Have you considered any alternatives?

I currently open up Schildichat to do this.

### Additional context

_No response_

### Are you willing to provide a PR?

No