Reduce extra spacing in the new tree and items tab (#1951)

* reduce layout row size and default font size

* icons for the tree

* refmt and update snapshots

* remove commented out code

src/Explorer/Controls/TreeComponent/TreeNodeComponent.tsx

@@ -149,15 +149,16 @@ export const TreeNodeComponent: React.FC<TreeNodeComponentProps> = ({
 
   // We use the expandIcon slot to hold the node icon too.
   // We only show a node icon for leaf nodes, even if a branch node has an iconSrc.
-  const expandIcon = isLoading ? (
-    <Spinner size="extra-tiny" />
-  ) : !isBranch ? (
-    typeof node.iconSrc === "string" ? (
+  const treeIcon =
+    node.iconSrc === undefined ? undefined : typeof node.iconSrc === "string" ? (
       <img src={node.iconSrc} className={treeStyles.nodeIcon} alt="" />
     ) : (
       node.iconSrc
-    )
-  ) : openItems.includes(treeNodeId) ? (
+    );
+
+  const expandIcon = isLoading ? (
+    <Spinner size="extra-tiny" />
+  ) : !isBranch ? undefined : openItems.includes(treeNodeId) ? (
     <ChevronDown20Regular data-test="TreeNode/CollapseIcon" />
   ) : (
     <ChevronRight20Regular data-text="TreeNode/ExpandIcon" />
@@ -174,7 +175,6 @@ export const TreeNodeComponent: React.FC<TreeNodeComponentProps> = ({
       <TreeItemLayout
         className={mergeClasses(
           treeStyles.treeItemLayout,
-          expandIcon ? undefined : treeStyles.treeItemLayoutNoIcon,
           shouldShowAsSelected && treeStyles.selectedItem,
           node.className && treeStyles[node.className],
         )}
@@ -200,6 +200,7 @@ export const TreeNodeComponent: React.FC<TreeNodeComponentProps> = ({
             ),
           }
         }
+        iconBefore={treeIcon}
         expandIcon={expandIcon}
       >
         <span className={treeStyles.nodeLabel}>{node.label}</span>