Make a dashboard its widgets: drop the pages and sections nobody drew

frontend/tests/editor.spec.ts

@@ -48,7 +48,7 @@ test.beforeAll(async ({ browser }) => {
   dashboard.columns = 12
   dashboard.canvas_width = 1920
   dashboard.canvas_height = 1080
-  dashboard.pages[0].sections[0].widgets = WIDGETS
+  dashboard.widgets = WIDGETS
   await api(page, `/dashboards/${dashboardName}`, {
     method: "PUT",
     data: dashboard,
@@ -65,7 +65,7 @@ async function placements(page: Page) {
   const doc = await (
     await api(page, `/dashboards/${dashboardName}?draft=true`)
   ).json()
-  const widgets = doc.pages[0].sections[0].widgets as {
+  const widgets = doc.widgets as {
     id: string
     layout: { lg: { x: number; y: number } }
   }[]