Add ability to hide tray icon on non-Mac (which has no tray icon)

[t3chguy]

Fixes #8904
Requires matrix-org/matrix-react-sdk#3573

[dbkr]

I'm very confused between this option and the existing 'minimise to tray' option. Shouldn't 'minimise to tray' be all that's needed here? Or at least would be if it worked correctly, but it looks like when 'minimise to tray' is disabled, the tray icon is still shown but closing the window closes the whole app. Also the 'minimise to tray' is shown in macOS which it shouldn't be because there isn't one.

What I'd expect would be one option which is shown on Linux & Windows. By default it's enabled in which case the tray icon is shown, when the window is closed riot continues to run in the background and clicking the tray icon shows the window again. When it's disabled, no tray icon is shown at all and closing the window causes the app to exit.

[t3chguy]

on Windows for example what if you want a tray icon but want the Close button to actually close rather than collapse to tray, clicking on the tray icon would minimize to tray.

On Mac the option should say Minimize to Dock, unchecking it makes X actually close the app fully.

As shown in Spotify, disabling minimize to tray does not get rid of the tray icon:

and identically in Discord:

[dbkr]

On Mac the option should say Minimize to Dock, unchecking it makes X actually close the app fully.

ARGH - you're right! It definitely shouldn't be doing this - this just isn't a thing that apps do on macOS.

As shown in Spotify, disabling minimize to tray does not get rid of the tray icon:

Ah, surprising, but OK: should we not follow suit from Spotify & Discord then and just have one option that controls the behaviour when closing the window, and the option doesn't appear on mac at all?

[t3chguy]

ARGH - you're right! It definitely shouldn't be doing this - this just isn't a thing that apps do on macOS.

Fair enough, am not a Mac user so do not know what behaviours are sub-par even as an option

Ah, surprising, but OK: should we not follow suit from Spotify & Discord then and just have one option that controls the behaviour when closing the window, and the option doesn't appear on mac at all?

I'm not against merging the two options and disallowing X = Close but show tray icon, @lampholder thoughts?