Empty right margin with read recipts disabled on IRC style layout

[meain]

Description

The right margin in Element desktop (on macOS) seems to retain the right edge even if read receipts are disabled in the IRC style layout. Related issue: #4248 . It seems to work fine in default mode, but does not seem to take effect when using IRC style display. This kinda make it a harder to use when the app is not able to use full width.

Version information

• Platform: Desktop
• OS: macOS
• Version: Element version: 1.7.23 - olm version: 3.2.1

[samhh]

I'm not familiar enough with that code to feel confident in making a PR that doesn't break other things, but locally it looked like changing .mx_EventTile_msgOption in the React SDK to have a max-width as opposed to a fixed width vastly improved matters. In an ideal world that JSX doesn't even get rendered if there's nothing relevant to put there, though.