favIconUrl is sometimes undefined on action (tab) (Firefox only?)

[kjeldahl]

In https://github.com/alyssaxuu/omni/blob/master/src/content.js#L72 the action.favIconUrl is sometime undefined for tab actions which will then cause a network request to /undefined.

It fails to load the image and the error handler shows the globe instead.

I guess it would be better to just show globe immediately when favIconUrl is undefined to avoid a failing request in the log.

I have only noticed this on Firefox (currently running v107.0.1 on Mac M1)

[mattsches]

I think I have the same issue here (Firefox, Ubuntu), and it's particularly annoying while developing/debugging web applications - the extra request really shouldn't happen.