✅(frontend) enhance document grid tests and component interactions

- Updated test cases to replace 'docs-grid-loader' with 'grid-loader'
for improved consistency across document grid tests.
- Refactored document interaction tests to utilize the 'docs-grid'
locator for better readability and maintainability.
- Enhanced document table content tests by refining element selection
methods for improved clarity and performance.
- Cleaned up test code to ensure better structure and maintainability.

src/frontend/apps/e2e/__tests__/app-impress/doc-create.spec.ts

@@ -18,11 +18,11 @@ test.describe('Doc Create', () => {
     const header = page.locator('header').first();
     await header.locator('h2').getByText('Docs').click();
 
-    await expect(page.getByTestId('docs-grid-loader')).toBeVisible();
+    await expect(page.getByTestId('grid-loader')).toBeVisible();
 
     const docsGrid = page.getByTestId('docs-grid');
     await expect(docsGrid).toBeVisible();
-    await expect(page.getByTestId('docs-grid-loader')).toBeHidden();
+    await expect(page.getByTestId('grid-loader')).toBeHidden();
     await expect(docsGrid.getByText(docTitle)).toBeVisible();
   });
 });