test(e2e/studio): drop racy post-action waits in database specs (from #46424) (#47106)

Follow-up to #47077, extracted from the TanStack Start migration
(#46424).

Three `waitForResponse` waits in `database.spec.ts` were registered
*after* their triggering action, so the response could resolve before
the listener attached and the wait would time out (this surfaced under
TanStack, where the data is SSR-streamed, but the waits are redundant on
Next too).

**Removed:**
- Schema Visualizer *actions*:
`waitForSchemaVisualizerToLoad(...'auth')` registered after the
schema-selector click — the `focusTableInVisualizer` loop immediately
below already auto-waits for the auth schema's tables.
- table update / duplicate: `waitForDatabaseToLoad(...)` after the save
mutation — the `toBeVisible` assertion right after each already waits
for the list to refetch.
- the now-unused `waitForDatabaseToLoad` /
`waitForSchemaVisualizerToLoad` imports.

The UI assertions are the real synchronization points, so behaviour is
unchanged on Next.

## To test
- Studio E2E `database.spec.ts` passes (the Schema Visualizer + Tables
groups).


<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

* **Tests**
* Improved database e2e test reliability by optimizing synchronization
logic and eliminating timing-sensitive helpers that could introduce
flakiness during schema and table operations.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Co-authored-by: Alaister Young <10985857+alaister@users.noreply.github.com>

e2e/studio/features/database.spec.ts

@@ -6,12 +6,7 @@ import { createTable, dropTable, query } from '../utils/db/index.js'
 import { dismissToastsIfAny } from '../utils/dismiss-toast.js'
 import { test, withSetupCleanup } from '../utils/test.js'
 import { toUrl } from '../utils/to-url.js'
-import {
-  createApiResponseWaiter,
-  waitForApiResponse,
-  waitForDatabaseToLoad,
-  waitForSchemaVisualizerToLoad,
-} from '../utils/wait-for-response.js'
+import { createApiResponseWaiter, waitForApiResponse } from '../utils/wait-for-response.js'
 
 async function focusTableInVisualizer(page: Page, tableName: string) {
   await page.getByTestId('find-table-selector').click()
@@ -88,8 +83,12 @@ test.describe('Database', () => {
       // changing schema -> auth
       await page.getByTestId('schema-selector').click()
       await page.getByRole('option', { name: 'auth' }).click()
-      await waitForSchemaVisualizerToLoad(page, ref, 'auth')
 
+      // No waitForResponse for auth-infinite_tables here: it fires on the
+      // schema switch above and can resolve before a listener registered now
+      // attaches (and is SSR-streamed under TanStack) — the same race that
+      // flaked this test. focusTableInVisualizer below already auto-waits for
+      // the auth schema's tables to load.
       for (const tableName of ['users', 'sso_providers', 'saml_providers']) {
         await focusTableInVisualizer(page, tableName)
         await expect(page.getByText(tableName, { exact: true })).toBeVisible()
@@ -340,9 +339,9 @@ test.describe('Database', () => {
       )
       await page.getByRole('button', { name: 'Save' }).click()
 
-      // validate table update
+      // validate table update — the toBeVisible assertion below already waits
+      // for the list to refetch, so no racy post-mutation waitForResponse here.
       await updateTableWait
-      await waitForDatabaseToLoad(page, ref)
       await expect(page.getByText(databaseTableNameUpdated, { exact: true })).toBeVisible()
       await expect(
         page.getByText(`Successfully updated ${databaseTableNameUpdated}!`)
@@ -362,9 +361,9 @@ test.describe('Database', () => {
       const duplicateTableWait = createApiResponseWaiter(page, 'pg-meta', ref, 'query?key=')
       await page.getByRole('button', { name: 'Save' }).click()
 
-      // validate table duplicate
+      // validate table duplicate — the toBeVisible assertion below already
+      // waits for the list to refetch, so no racy post-mutation wait here.
       await duplicateTableWait
-      await waitForDatabaseToLoad(page, ref)
       await expect(page.getByText(databaseTableNameDuplicate, { exact: true })).toBeVisible()
       await expect(
         page.getByText(