IssueTracker

Description

There doesn't appear that there's any method to support custom emoji reactions with spaces.messages.reactions.create

What I would love to see is "something" like:

• spaces.emoji.list
• spaces.emoji.create
• spaces.emoji.get

and so on with support for custom emoji when using spaces.messages.reactions.create. For the sake of symmetry though I think I'd love to add custom emojis by name, using the uid would be fine if it's easy to lookup.

Impact

Currently working on an import from mattermost and I've encountered the following:

1. No way to import all custom emoji into Google (we've got over 400). It's currently manual through the UI
2. Even if the emojis are in place, it doesn't appear there's a way to import old reactions with spaces.messages.reactions.create a. there's no documented method of mapping custom_emoji_name to a uid b. even if I track down the proper uid, using the create method yields the error Invalid emoji. Only Unicode emoji are supported.

This seems to go well with the other ticket: Support for :emoji: in text messages and webhooks

Later on, being able to map the customEmoji's uid back to something like merge-branch or reboot-service would be super great for bot interactions.