Merge Expires and Max-Age attributes

[imvtsl]

org.springframework.http.client.reactive.ClientHttpResponse and its implementations don't process Expires Cookie attribute. However, they only process Max-Age attribute.

Logic defined in RFC 6265. Point 3 of section 5.3 in this RFC gives higher precedence to Max-Age over Expires. This change follows this RFC and does the following: 1- If both Max-Age and Expires attribute are present in the cookie, set maxAge field in ResponseCookie to Max-Age attribute. 2- If only Expires attribute is present in the cookie, set maxAge field in ResponseCookie to Expires attribute. 2- If only Max-Age attribute is present in the cookie, set maxAge field in ResponseCookie to Max-Age attribute.

Closes https://github.com/spring-projects/spring-framework/issues/33157

[imvtsl]

@sbrannen please review.

[sbrannen]

Thanks for the PR, @imvtsl!

I'll take a look at it in the coming days.

[bclozel]

Sorry for the late feedback @imvtsl In the end, we went with a simpler approach in #33157 as this PR was creating new public API and the tests were too involved.

Thanks for your contribution!