Update README for browser testing commands (#10541)

## Summary

Update recommended commands in browser_tests README

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-10541-Update-README-for-browser-testing-commands-32f6d73d36508175a675e865a990caed)
by [Unito](https://www.unito.io)

---------

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

browser_tests/README.md

@@ -75,7 +75,7 @@ For tests that specifically need to test release functionality, see the example
 **Always use UI mode for development:**
 
 ```bash
-pnpm exec playwright test --ui
+pnpm test:browser:local --ui
 ```
 
 UI mode features:
@@ -91,29 +91,8 @@ UI mode features:
 For CI or headless testing:
 
 ```bash
-pnpm exec playwright test                    # Run all tests
-pnpm exec playwright test widget.spec.ts     # Run specific test file
-```
-
-### Local Development Config
-
-For debugging, you can try adjusting these settings in `playwright.config.ts`:
-
-```typescript
-export default defineConfig({
-  // VERY HELPFUL: Skip screenshot tests locally
-  grep: process.env.CI ? undefined : /^(?!.*screenshot).*$/
-
-  retries: 0, // No retries while debugging. Increase if writing new tests. that may be flaky.
-  workers: 1, // Single worker for easier debugging. Increase to match CPU cores if you want to run a lot of tests in parallel.
-  timeout: 30000, // Longer timeout for breakpoints
-
-  use: {
-    trace: 'on', // Always capture traces (CI uses 'on-first-retry')
-    video: 'on' // Always record video (CI uses 'retain-on-failure')
-  },
-
-})
+pnpm test:browser:local                    # Run all tests
+pnpm test:browser:local widget.spec.ts     # Run specific test file
 ```
 
 ## Test Structure
@@ -385,7 +364,7 @@ export default defineConfig({
 Option 2 - Generate local baselines for comparison:
 
 ```bash
-pnpm exec playwright test --update-snapshots
+pnpm test:browser:local --update-snapshots
 ```
 
 ### Creating New Screenshot Baselines