fix(webkit): make cookie SameSite=Lax by default

[yury-s]

“Prevent cross-site tracking” feature is on by default in Safari. It prevents SameSite=None cookie behavior, making such cookies Lax. With this PR the following behavior changes:

• The following cookies become SameSite=Lax when added via addCookies call:

  • SameSite is not specified
  • SameSite=None is specified

• Cookies added via document.cookies='foo=bar' are now reported as Lax.

Reference #30305
Reference https://github.com/microsoft/playwright-browsers/issues/795

[yury-s]

This is based on mxschmitt@0b6e317

[github-actions]

Test results for "tests 1"

9 failed
❌ [playwright-test] › playwright.ct-react.spec.ts:253:5 › should pass "key" attribute from JSX in variable
❌ [webkit-library] › library/browsercontext-cookies.spec.ts:24:3 › should get a cookie @smoke
❌ [webkit-library] › library/browsercontext-cookies.spec.ts:43:3 › should get a non-session cookie
❌ [webkit-library] › library/browsercontext-cookies.spec.ts:112:3 › should get multiple cookies
❌ [webkit-library] › library/browsercontext-cookies.spec.ts:353:3 › should support requestStorageAccess
❌ [webkit-library] › library/browsercontext-fetch.spec.ts:1205:3 › should support set-cookie with SameSite and without Secure attribute over HTTP
❌ [webkit-library] › library/browsercontext-route.spec.ts:112:3 › should support Set-Cookie header
❌ [webkit-library] › library/browsercontext-route.spec.ts:155:3 › should use Set-Cookie header in future requests
❌ [webkit-library] › library/defaultbrowsercontext-1.spec.ts:22:3 › context.cookies() should work @smoke

1 flaky

⚠️ [playwright-test] › ui-mode-test-screencast.spec.ts:21:5 › should show screenshots

27047 passed, 609 skipped
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Merge workflow run.