standard emoji are not available? Only custom emoji.

**Describe the bug**
Only the mastodon.social custom emoji seem to be available, not the full set of emjoi that I can normally insert via short codes on mastodon.social.
- Which site: phanpy.social

**To Reproduce**
Steps to reproduce the behavior:
1. Go to 'create post'
2. Type ':open_mouth:' (that's 'open_mouth')

**Expected behavior**
I expect the :open_mouth: emjoi to appear or be selectable from the list of emoji's, as it is when I'm composing on mastodon.social. Instead, I get suggestions only for the custom emoji's that mastodon.social provides. None of the other "standard" emoji seem to show up, or be in the dropdown list either.

**Desktop (please complete the following information):**
- OS: Pop!OS (Ubuntu based)
- Browser: Edge Version 113.0.1754.0 (Official build) dev (64-bit)

Start by reproducing the issue in the create post composer with :open_mouth: and inspect the emoji suggestions or dropdown entry point. Trace how custom Mastodon emoji are loaded and how standard emoji are handled; done means standard emoji such as :open_mouth: appear or can be selected alongside custom emoji.

Written by the indexing model from the issue text.