Please add an option to disable automatically setting focus for the input box

### Your use case

#### What would you like to do?
Add an option to disable automatically setting focus for the input box.

#### Why would you like to do it?
Because I use `vimium` extension in `chromium`, everytime when I open up a room, element-web will automatically set focus for the input box, then I can't operate the webpage with keyboards unless I press the `esc` key first.
Althrough `vimium` provide an option which is `Don't let pages steal the focus on load`, but it doesn't work well, so I never enabled it.

#### How would you like to achieve it?
No idea.

### Have you considered any alternatives?

Like I said before, if I enable the option which `vimium` has provided, it will only work after the webpage has loaded first by browser, so it's not a good solution.

### Additional context

_No response_

No source file or test is named. Start by tracing where Element Web focuses the input box when a room opens, then identify how user options are defined and applied; done means users can disable that automatic focus while normal focus behavior remains unchanged.

Written by the indexing model from the issue text.