* Don't consider textual characters to be emoji
We were using emojibase-regex to match emoji within messages. However, the docs (https://emojibase.dev/docs/regex/) state that this regex matches both emoji and text presentation characters. This is not what we want, and will result in false positives for characters like '↔' that could turn into an emoji if paired with a variation selector. Unfortunately, none of the other regexes provided by Emojibase do what we want either (https://github.com/milesj/emojibase/issues/174). In the meantime, browser support for the RGI_Emoji character sequence class has made it feasible to write an emoji regex by hand, so that's what I've done.
* Add a fallback for BIGEMOJI_REGEX as well
c61eca8c24