Fix: improve accessibility for icon buttons (Table Editor menu) (#47639)

## I have read the
[CONTRIBUTING.md](https://github.com/supabase/supabase/blob/master/CONTRIBUTING.md)
file.

YES

## What kind of change does this PR introduce?

Bug fix (accessibility improvement)

## What is the current behavior?

Icon-only buttons do not have explicit accessible names for screen
readers or tooltips.

## What is the new behavior?

All icon-only buttons now have explicit accessible names using visually
hidden text (sr-only), ensuring proper screen reader support.

## Additional context

Tooltip text is preserved or added for visual users.
No visual changes were introduced.


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

* **Accessibility Improvements**
* Updated table editor action controls with clearer, context-aware
`aria-label`s (e.g., “Add new column”, “More options for …”, “New
table”).
* **UI Refinements**
* Added hover tooltips to key table editor actions, including
add-column, more-options dropdown triggers, and create-new-table button,
improving discoverability and guidance.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

e2e/studio/features/queue-table-operations.spec.ts

@@ -15,7 +15,7 @@ const enableQueueOperations = async (page: Page) => {
 }
 
 const openQueueDropdownAndClick = async (page: Page, itemName: string) => {
-  await page.getByRole('button', { name: 'More options' }).click()
+  await page.getByRole('button', { name: 'More options', exact: true }).click()
   await page.getByRole('menuitem', { name: itemName }).click()
 }