respect readonly connection flag in table editor

packages/web/src/buttons/DropDownButton.svelte

@@ -8,9 +8,12 @@
   export let icon = 'icon chevron-down';
   export let menu;
   export let narrow = false;
+  export let disabled = false;
   let domButton;
 
   function handleClick() {
+    if (disabled) return;
+    
     const rect = domButton.getBoundingClientRect();
     const left = rect.left;
     const top = rect.bottom;
@@ -18,6 +21,6 @@
   }
 </script>
 
-<InlineButton square {narrow} on:click={handleClick} bind:this={domButton}>
+<InlineButton square {narrow} on:click={handleClick} bind:this={domButton} {disabled}>
   <FontIcon {icon} />
 </InlineButton>