No focus on popover when "searchable" is false

[varacti]

Description :

By setting the props searchable to false, the use of the "MultiSelect" component becomes impossible with only the keyboard.

We can focus the main component and each selected options inside of it and interact with them.

Pressing "enter" on the main component opens the popover of the options but do not let us interact with the items inside of it.

Reproduction :

• Go to the live demo : https://shadcn-multi-select-component.vercel.app/
• Go to the card "Search and UI Configuration"
• Click on the title of the right multi-select "Simplified Interface"
• Press "Tab" on keyboard to focus the multi-select
• Press "Enter" on keyboard to open the popover
• Press "Arrow up/Arrow down/Space/Enter", the page move/scroll instead of selecting/moving the focus in the popover.