Repository: vercel/next.js
Pull request: [test] Deflake `browser-log-forwarding verbose level` test suite

[flakiness metric](https://app.datadoghq.com/ci/test/runs?query=test_level%3Atest%20%40git.repository.id%3A%22github.com%2Fvercel%2Fnext.js%22%20%40test.name%3A%22browser-log-forwarding%20verbose%20level%20should%20forward%20all%20logs%20to%20terminal%22%20%40test.type%3A%22nextjs%22%20%40test.status%3Afail&agg_m=count&agg_m_source=base&agg_t=count&fromUser=false&index=citest&start=1769207121512&end=1769811921512&paused=false)

The test frequently failed because it snapshot-asserted on the forwarded browser logs before the final debug message was forwarded. This is because the initial assertion inside the `retry` block would pass because it falsely matched the debug message inside the error code frame (line 11):

```
[browser] browser error: this is an error message
    at Page.useEffect (app/page.tsx:10:13)
   8 |     console.info('browser info: this is an info message')
   9 |     console.warn('browser warn: this is a warning message')
> 10 |     console.error('browser error: this is an error message')
     |             ^
  11 |     console.debug('browser debug: this is a debug message')
  12 |   }, [])
  13 | (app/page.tsx:10:13)
```

By adding the `[browser] ` prefix to all expected log messages, we ensure that the test only passes when the actual log messages are forwarded, and not when they appear inside code frames.

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Changed files:
filename: test/development/app-dir/browser-log-forwarding/fixtures/verbose-level/verbose-level.test.ts
patch: @@ -12,10 +12,10 @@ describe('browser-log-forwarding verbose level', () => {
 
     await retry(() => {
       const output = next.cliOutput.slice(outputIndex)
-      expect(output).toContain('browser error:')
-      expect(output).toContain('browser warn:')
-      expect(output).toContain('browser log:')
-      expect(output).toContain('browser debug:')
+      expect(output).toContain('[browser] browser error:')
+      expect(output).toContain('[browser] browser warn:')
+      expect(output).toContain('[browser] browser log:')
+      expect(output).toContain('[browser] browser debug:')
     })
 
     // Get final output after logs are forwarded