hotfix(multi-select): prevent double trigger in a filterable multiseelct (#954)

Fixes #940

Author: metonym

Diff for: src/MultiSelect/MultiSelect.svelte

@@ -454,6 +454,7 @@
           />
         {/if}
         <ListBoxMenuIcon
+          style="pointer-events: {open ? 'auto' : 'none'}"
           on:click="{(e) => {
             e.stopPropagation();
             open = !open;