Revert "Test DataGrid schema-pending loading skeleton."

This reverts commit 08e9527d04.

packages/dashboard-ui-components/src/components/data-grid/data-grid.test.tsx

@@ -611,60 +611,3 @@ describe("DataGrid horizontal scrolling", () => {
     expect((bodyScroll as HTMLElement).scrollLeft).toBe(120);
   });
 });
-
-describe("DataGrid loading skeleton", () => {
-  beforeEach(() => {
-    vi.stubGlobal("ResizeObserver", MockResizeObserver);
-  });
-
-  afterEach(() => {
-    cleanup();
-    vi.restoreAllMocks();
-    vi.unstubAllGlobals();
-  });
-
-  it("shows a full-width shimmer when loading before any columns are known", () => {
-    function SchemaPendingHarness() {
-      const [state, setState] = useState(() => createDefaultDataGridState([]));
-      return (
-        <DataGrid<Row>
-          columns={[]}
-          rows={[]}
-          getRowId={(row) => row.id}
-          state={state}
-          onChange={setState}
-          isLoading
-        />
-      );
-    }
-
-    const { container } = render(<SchemaPendingHarness />);
-
-    const skeleton = container.querySelector("[data-data-grid-schema-pending-skeleton]");
-    expect(skeleton).toBeInstanceOf(HTMLElement);
-    // Five placeholder columns × 10 rows → visible shimmer cells, not an empty pane.
-    expect(skeleton?.querySelectorAll("[role='row']").length).toBe(10);
-  });
-
-  it("uses per-column skeleton rows once the schema is known", () => {
-    function KnownSchemaHarness() {
-      const [state, setState] = useState(() => createDefaultDataGridState(columns));
-      return (
-        <DataGrid<Row>
-          columns={columns}
-          rows={[]}
-          getRowId={(row) => row.id}
-          state={state}
-          onChange={setState}
-          isLoading
-        />
-      );
-    }
-
-    const { container } = render(<KnownSchemaHarness />);
-
-    expect(container.querySelector("[data-data-grid-schema-pending-skeleton]")).toBeNull();
-    const rowsClip = container.querySelector("[data-data-grid-rows-clip]");
-    expect(rowsClip?.querySelectorAll("[role='row']").length).toBe(8);
-  });
-});