Add a Behavior preference to disable the emoji autocomplete picker

Description

When typing colons at the end of French sentences like:

Et voilà :

The emoji picker pops up. Users who don't use emoji find this disruptive, and it interferes with natural typing in languages where colons are preceded by a non-breakable space.

Proposal

Add a user preference toggle under User Settings > Preferences > Behavior to disable the emoji autocomplete picker.

• Default: Enabled (preserving current behavior for existing users)
• When disabled: The emoji autocomplete picker will not appear when typing : in text fields
• Users can still insert emoji via other means (e.g., the emoji button in the toolbar, copy-paste)

Additional Considerations

• documentation will need to be updated to reflect the new preference option
• A release post item will be needed to announce this change
• We will need to track this behaviour (e.g., via usage tracking / internal analytics) to understand adoption and validate the decision