fix: hide the tree root when selecting a master template

src/Umbraco.Web.UI.Client/src/packages/templating/templates/workspace/template-workspace-editor.element.ts

@@ -126,6 +126,7 @@ export class UmbTemplateWorkspaceEditorElement extends UmbLitElement {
 				pickableFilter: (item) => {
 					return item.unique !== null && item.unique !== this.#templateWorkspaceContext?.getEntityId();
 				},
+				hideTreeRoot: true,
 			},
 			value: {
 				selection: [this.#masterTemplateUnique],