Revert "(TreeNode): remove a switch that wouldn't be required"

This reverts commit d9d94d4.

Author: msmx-mnakagawa

src/scripts/TreeNode.tsx

@@ -98,13 +98,22 @@ const TreeNodeItem: FC<TreeNodeProps & { icon?: string }> = (props) => {
         />
       ) : null}
       <span className='slds-has-flexi-truncate'>
-        <a
-          className='slds-tree__item-label slds-truncate'
-          tabIndex={-1}
-          onClick={onLabelClick}
-        >
-          {ItemRender ? <ItemRender {...props} /> : label}
-        </a>
+        {onLabelClick ? (
+          <a
+            className='slds-tree__item-label slds-truncate'
+            tabIndex={-1}
+            onClick={onLabelClick}
+          >
+            {ItemRender ? <ItemRender {...props} /> : label}
+          </a>
+        ) : (
+          <span
+            className='slds-tree__item-label slds-truncate'
+            title={typeof label === 'string' ? label : undefined}
+          >
+            {ItemRender ? <ItemRender {...props} /> : label}
+          </span>
+        )}
       </span>
       {leaf ? children : null}
     </div>