Custom emojis not rendered in sidebar last message preview

Description:

Custom emojis do not render correctly in the Group List sidebar last message preview.
Instead of displaying the custom emoji , the sidebar shows the raw shortcode, for example :custom_emoji_name: Standard Unicode emojis render correctly in the same location.

This issue only affects the sidebar last message preview. Custom emojis render correctly inside the main chat message view and in reaction.

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Steps to reproduce:

1. Upload a custom emoji, for example with the shortcode :rinx:
2. Open any channel or group.
3. Send a message containing the custom emoji.
4. Observe the Group List sidebar on the left.
5. Check the last message preview for that group.

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Expected behavior:

The custom emoji should be rendered as a emoji in the sidebar last message preview,
similar to how:

• it appears inside the chat message
• standard Unicode emojis appear in the sidebar

Actual behavior:

The custom emoji is displayed as raw text in the sidebar last message preview, for example :rinx:

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Server Setup Information:

• Version of Rocket.Chat Server: develop branch latest
• License Type:
• Number of Users:
• Operating System: Linux
• Deployment Method:
• Number of Running Instances:
• DB Replicaset Oplog:
• NodeJS Version: 22.16.0
• MongoDB Version:

Client Setup Information

• Desktop App or Browser Version:
• Operating System: Linux

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Additional context

video

https://github.com/user-attachments/assets/34ad6087-6dfe-4b0a-a456-df5e942f994b

Relevant logs:

none.

Start at the Group List sidebar last-message preview and compare its emoji handling with the main chat message and reaction views, which the issue says render custom emojis correctly. Follow the reproduction steps with a custom shortcode such as :rinx:; done means the sidebar preview renders the custom emoji instead of its raw shortcode while Unicode emoji behavior remains unchanged.