Make Share on Twitter Work on Mobile Too

[danbugs]

Describe the solution you'd like
Currently, the "Share on Twitter" feature is blocked on mobile because of the way we're currenty screenshotting the DOM w/ html2canvas. If enabled, mobile shares look wonky like:

... so it was disabled. To fix this, we'd probably have to make some sort of changes to the CSS to generate smt that works regarless of screen size but is still optimal for a Twitter card.

Additional context
Side note: W/ this, let's also investigate it possibly not working on medium screen sizes. I tried setting the screensize to the iPad Pro option, but I get an error from the image-upload-backend w/:

Side note 2: The wonky example was actually captured from my computer w/ an emulation of the phone size. On the phone, for some reason, the image-upload-backend also fails and this probably warrants more investigation too.