chore(bidi): handle CORS preflight requests

[hbenl]

Fixes the following tests in page/page-event-request.spec.ts:

• "should not expose preflight OPTIONS request"
• "should not expose preflight OPTIONS request with network interception"

[yury-s]

I don't know about other types, but marking preflight sounds non-controversial.

[hbenl]

I've changed the condition to if (param.initiator?.type === 'preflight' || requestHeaders['access-control-request-method'])

[github-actions]

Test results for "tests 1"

4 failed
❌ [playwright-test] › playwright.trace.spec.ts:137 › should not throw with trace: on-first-retry and two retries in the same worker @macos-latest-node20
❌ [playwright-test] › reporter-junit.spec.ts:310 › created › should render existing attachments, but not missing ones @macos-latest-node20
❌ [playwright-test] › reporter-line.spec.ts:193 › merged › should show error context with relative path @macos-latest-node20
❌ [playwright-test] › reporter.spec.ts:251 › created › should not have internal error when steps are finished after timeout @macos-latest-node20

4 flaky

⚠️ [chromium-page] › page/page-request-continue.spec.ts:754 › propagate headers cross origin redirect after interception `@chromium-ubuntu-22.04-arm-node20`
⚠️ [chromium-library] › library/popup.spec.ts:258 › should not throw when click closes popup `@chromium-ubuntu-22.04-node22`
⚠️ [firefox-library] › library/trace-viewer.spec.ts:1241 › should update highlight when typing locator `@firefox-ubuntu-22.04-node20`
⚠️ [webkit-page] › page/page-autowaiting-basic.spec.ts:79 › should await form-post on click `@webkit-ubuntu-22.04-node20`

38551 passed, 843 skipped

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Merge workflow run.

[github-actions]

Test results for "MCP"

1 failed
❌ [chrome] › mcp/http.spec.ts:149 › http transport browser lifecycle (isolated, multiclient) @mcp-macos-15

4778 passed, 135 skipped

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Merge workflow run.