fix(fuselage): ensure MultiSelect dropdown closes on addon click

[Vrund4591]

Closes #1305

Description

The MultiSelect dropdown was failing to close when clicking the addon icon (chevron) because the click event was bubbling up to the container, causing the menu to immediately re-open.

This PR fixes the issue by:

1. Adding e.stopPropagation() to the SelectAddon click handler to stop the event bubbling.
2. Adding onMouseDown={(e) => e.preventDefault()} to prevent focus loss (blur) which was causing conflicting toggle states.

Changes

• Added handleAddonClick handler to MultiSelect.tsx.
• Applied onMouseDown prevention to SelectAddon.

Verification

1. Open Storybook > MultiSelect > Default.
2. Click the input to open the dropdown.
3. Click the chevron icon.
4. Validated that the dropdown now closes correctly without bouncing back open.

[changeset-bot]

🦋 Changeset detected

Latest commit: a82cf4e

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@rocket.chat/fuselage	Patch

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