Update Tree example to not have first item selected

This allows manual testing of setting tabIndex/focus not on the first item.

Author: interactivellama

components/tree/__tests__/tree.browser-test.jsx

@@ -313,9 +313,10 @@ describe('Tree: ', () => {
 
 		it('has initial selection', function () {
 			let selectedNode = this.wrapper
-				.find('#example-tree-1')
+				.find('#example-tree-2')
 				.find('.slds-is-selected');
-			expect(selectedNode).to.have.length(1);
+			// Fruits, Watermelon, Tree Fruits
+			expect(selectedNode).to.have.length(3);
 			selectedNode = this.wrapper
 				.find('#example-tree-5')
 				.find('.slds-is-selected');

utilities/sample-data/tree/sample-nodes-with-initial-state.jsx

@@ -3,23 +3,25 @@ const treeNodesWithInitialState = [
 		label: 'Grains',
 		type: 'item',
 		id: 1,
-		selected: true,
 	},
 	{
 		label: 'Fruits',
 		type: 'branch',
 		id: 2,
 		expanded: true,
+		selected: true,
 		nodes: [
 			{
 				label: 'Ground Fruits',
 				type: 'branch',
 				id: 4,
+				expanded: true,
 				nodes: [
 					{
 						label: 'Watermelon',
 						type: 'item',
 						id: 12,
+						selected: true,
 					},
 					{
 						label: 'Canteloupe',