Emoji gets inserted one character earlier than it should (?)

[nonnullish]

It seems that the emoji get inserted one character earlier than they should.

Tested on: iPhone 11 with iOS 17.3.1, Elk v0.11.0 installed as a PWA / bookmark.
Steps to reproduce:

1. Compose a new post, write for example "12345".
2. Move cursor between 3 and 4 and insert an emoji from the emoji keyboard.
3. The emoji appears between 2 and 3.

Here's a screen recording:
https://github.com/elk-zone/elk/assets/20538005/1258c4c4-3aee-4f3f-90b8-c25c17a24acf

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[shuuji3]

I also observed the same issue when I inserted an emoji but in my case with the IME conversion.

• Version: Elk v0.11.0 / Canary 6dc5a68
• macOS (Google Japanese IME) / Linux (mozc)
• Google Chrome / Firefox

emoji-left-insert.mp4

Maybe the calculation of the insertion position is incorrect in case the inserted character type is emoji. I don't see this shift issue when inserting Japanese characters.