test(i18n): expect the German chart column label

The dashboard layout test pinned the German column header as "Chart",
the English word the catalog carried until it was translated.

src/components/settings/__tests__/dashboard-layout-section.test.tsx

@@ -111,7 +111,7 @@ describe("<DashboardLayoutSection> — tile + chart split", () => {
   it("renders both column headers in German", () => {
     const html = render(<DashboardLayoutSection id="dashboard-layout" />, "de");
     expect(html).toContain("Kachel");
-    expect(html).toContain("Chart");
+    expect(html).toContain("Diagramm");
   });
 
   it("paints both switch slots per widget", () => {