OAuth2Login behaves differently in MVC and Reactive

[joaquinjsb]

Expected Behavior

When switching between MVC and Reactive variants, the behavior of the oauth2login should likely be the same, when using token relay with Spring Cloud Gateway.

Current Behavior

the DefaultOAuth2AuthorizationRequestResolver doesn't alter the defaultAction when the client grant is authorization code, the reactive stack changes the action urimap variable.
Context

spring-security/oauth2/oauth2-client/src/main/java/org/springframework/security/oauth2/client/web/server/DefaultServerOAuth2AuthorizationRequestResolver.java

Lines 253 to 255 in 62c5a25

	if (AuthorizationGrantType.AUTHORIZATION_CODE.equals(clientRegistration.getAuthorizationGrantType())) {
	action = "login";
	}

so when I'm using my tokenRelay in reactive spring cloud gateway, everything works as expected, but when working with MVC, the generated url, which starts here

spring-security/oauth2/oauth2-client/src/main/java/org/springframework/security/oauth2/client/web/DefaultOAuth2AuthorizationRequestResolver.java

Line 120 in 62c5a25

String redirectUriAction = getAction(request, "authorize");

generates an "invalid" URL, because the code doesn't interfere:

spring-security/oauth2/oauth2-client/src/main/java/org/springframework/security/oauth2/client/web/DefaultOAuth2AuthorizationRequestResolver.java

Line 250 in 62c5a25

uriVariables.put("action", (action != null) ? action : "");

when calling "authorize" signature generates this url:
/authorize/oauth2/code/{registrationId}......
while calling "login" generates a "valid" one:
/login/oauth2/code/{registrationId}....

*of course modifying manually the redirect-uri of the client solves the issue, but would be nice if the behavior is
valid