Add "Show hidden events in timeline" to quick settings if "Developer mode" is enabled

### Your use case

Requires #20683

#### What would you like to do?
When Developer mode is enabled per #20683, add a toggle for the commonly used "Show hidden events in timeline" to the new quick settings thingy in the space bar.

#### Why would you like to do it?
You would frequently want to toggle this setting to compare or quickly debug something while normally hiding events.
This is much easier with #20646, but I would argue that this is a fitting place in the UI if you can't remember, or the shortcut doesn't work on your keyboard layout, or you just want to check the current state of the toggle.

### Have you considered any alternatives?

_No response_

### Additional context

_No response_