test(databases): stabilize flaky SQLAlchemy-form visibility assertion

The form mounts inside DatabaseModal's animated tab pane, and
rc-motion's animation state in jsdom is nondeterministic: toBeVisible
intermittently times out (observed on unrelated PRs' jest shards) even
though the form is rendered. Assert on document presence instead, which
is what the tab-switch regression check actually needs.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

superset-frontend/src/features/databases/DatabaseModal/index.test.tsx

@@ -1804,8 +1804,14 @@ describe('DatabaseModal', () => {
 
     userEvent.click(screen.getByTestId('sqla-connect-btn'));
 
-    expect(await screen.findByTestId('database-name-input')).toBeVisible();
-    expect(screen.getByTestId('sqlalchemy-uri-input')).toBeVisible();
+    // assert on presence rather than visibility: the SQLAlchemy form mounts
+    // inside an animated tab pane, and rc-motion's animation state in jsdom
+    // is nondeterministic, so toBeVisible flakes while the form is in fact
+    // rendered (see the animated={{ tabPane: true }} Tabs in DatabaseModal)
+    expect(
+      await screen.findByTestId('database-name-input'),
+    ).toBeInTheDocument();
+    expect(screen.getByTestId('sqlalchemy-uri-input')).toBeInTheDocument();
   });
 
   test.each([