Thumbnail preview not posting if you press enter on a comment too quickly

just type a comment with link and press enter super fast. This happens to me ALL the time.

• We need to keep the keypress url resolution. It's inefficient from a request standpoint, but the interaction is nice.
• On each key press, resolve the urls. Collect the successes by url, ignore the errors
• Select the url preview that makes the current url in the comment/activity
• On enter, make sure the request resolves like any other key press and then submit the commit