chore(bidi): add support for network.setExtraHeaders

[hbenl]

Fixes #38060 and the following tests:

• tests/library/browsercontext-locale.spec.ts:
  • "should affect accept-language header"
• tests/library/browsercontext-set-extra-http-headers.spec.ts:
  • "should override extra headers from browser context"
• tests/library/defaultbrowsercontext-2.spec.ts:
  • "should support extraHTTPHeaders option"
• tests/library/popup.spec.ts:
  • "should inherit extra headers from browser context"
• tests/page/page-route.spec.ts:
  • "should show custom HTTP headers"
  • "should work with custom referer headers"
  • "should send referer"
• tests/page/page-set-extra-http-headers.spec.ts:
  • "should work"
  • "should work with redirects"
  • "should work with extra headers from browser context"
  • "should not duplicate referer header"

[github-actions]

Test results for "MCP"

2588 passed, 116 skipped

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Merge workflow run.

[github-actions]

Test results for "tests 1"

1 failed
❌ [playwright-test] › runner.spec.ts:118 › should ignore subprocess creation error because of SIGINT @macos-latest-node18-2

4 flaky

⚠️ [firefox-library] › library/inspector/cli-codegen-1.spec.ts:1079 › cli codegen › should not throw csp directive violation errors `@firefox-ubuntu-22.04-node18`
⚠️ [firefox-page] › page/page-emulate-media.spec.ts:144 › should keep reduced motion and color emulation after reload `@firefox-ubuntu-22.04-node18`
⚠️ [firefox-page] › page/page-goto.spec.ts:83 › should work with Cross-Origin-Opener-Policy `@firefox-ubuntu-22.04-node18`
⚠️ [playwright-test] › ui-mode-test-shortcut.spec.ts:103 › should toggle Terminal `@windows-latest-node18-2`

40317 passed, 789 skipped

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Merge workflow run.