feat: add button to collapse all in tree view (#17992) (#18003)

* Added button to collapse tree root node

* Removed unneccessary space

* Collapse all expanded nodes

* style: prettier

* refactor: load first level root nodes by default

Co-authored-by: Ankush Menat <ankush@frappe.io>
(cherry picked from commit e8b0b991ab)

Co-authored-by: Nikhil Kothari <nik.kothari22@live.com>

frappe/public/js/frappe/views/treeview.js

@@ -94,6 +94,10 @@ frappe.views.TreeView = class TreeView {
 		this.page.main.addClass("frappe-card");
 
 		if (this.opts.show_expand_all) {
+			this.page.add_inner_button(__("Collapse All"), function () {
+				me.tree.load_children(me.tree.root_node, false);
+			});
+
 			this.page.add_inner_button(__("Expand All"), function () {
 				me.tree.load_children(me.tree.root_node, true);
 			});