Icon disappears in "Step" when using german letters (ä, ö, ü)

[Th3R3alDuk3]

Description
When umlauts (ä, ö, ü) are included (e.g., in the step name), the associated icon/avatar fails to display, even though the umlauts themselves appear correctly in text fields.

Steps to Reproduce

import chainlit
import asyncio

async with chainlit.Step(name="Überprüfung") as step:
    await sleep(3)

Actual Behavior
The text (including umlauts) displays correctly, but the icon is missing or fails to render.

Environment
Operating System: (e.g., Ubuntu 24.04)
Browser/Version: (e.g., Chrome version 131.0.6778.204 (64-Bit))
Framework / Version: -

[dokterbob]

Probably related to #1420.