Add a fallback font for when FA is disabled

[SaschaMann]

The icons for formatting in the mentoring editor don't seem to have a fallback font. It's common practice to disable third-party fonts and/or google fonts as part of fingerprinting and tracking protection, so I imagine this will be encountered somewhat frequently.

[iHiD]

Just as an FYI, this is all part of the library, so fixing it will be quite a lot of work.

[SaschaMann]

I'd be fine with not having that bar at all in that case. It's a bit weird to have invisible buttons that are even highlighted sometimes.

[iHiD]

I'd be fine with not having that bar at all in that case.

Yeah - again, it would the challenge though. We'd have to hack the external library, and I'm not sure that font-detection is something that you can do easily. The app doesn't know whether your call to Google Fonts succeeds or not.

[iHiD]

(or in this case font-awesome)

[SleeplessByte]

The app doesn't know whether your call to Google Fonts succeeds or not.

FontFaceObserver can help us here. See: https://fontfaceobserver.com/