Add handling for cookies with the same name to DefaultCookieJar

[suzuki764]

Motivation:

The DefaultCookieJar does not handle cases where cookies with the same name are set.

Modifications:

• Added processing in accordance with RFC 6265:
  • Overwrites existing cookies when a cookie with the same name, domain, and path is set.
  • If the existing cookie has the HttpOnly flag set and the new cookie is created by a non-HTTP API, the new cookie is ignored.

Result:

• Correctly handles setting cookies with the same name.
• Closes CookieClient appends cookies with the same name #5870.

[github-actions]

🔍 Build Scan® (commit: e926c82)

Job name	Status	Build Scan®
build-ubicloud-standard-16-jdk-8	✅	https://ge.armeria.dev/s/7muuaw4pokdvm
build-ubicloud-standard-16-jdk-21-snapshot-blockhound	✅	https://ge.armeria.dev/s/3yue7pkhijddk
build-ubicloud-standard-16-jdk-17-min-java-17-coverage	✅	https://ge.armeria.dev/s/jwvv7bvhgyg3g
build-ubicloud-standard-16-jdk-17-min-java-11	✅	https://ge.armeria.dev/s/namokguh7awvs
build-ubicloud-standard-16-jdk-17-leak	✅	https://ge.armeria.dev/s/7bcv5p4wl3g52
build-ubicloud-standard-16-jdk-11	✅	https://ge.armeria.dev/s/sto63276l735g
build-macos-latest-jdk-21	✅	https://ge.armeria.dev/s/zri5fz7e2ypqy