[Reg 6.6.3 -> 6.7] QOAuth2AuthorizationCodeFlow uses "localhost" as the redirect URI when it should be "127.0.0.1"

Suppose we construct a reply handler like this:

auto handler = new QOAuthHttpServerReplyHandler(55555, this);

• Qt 6.6.3 would set the redirect URI to "http://127.0.0.1:55555" (Expected)
• Qt 6.7 and newer would set the redirect URI to "http://localhost:55555" (Not Expected)

Even using an explicit host address still results in "localhost" being used in the redirect URI:

auto handler = new QOAuthHttpServerReplyHandler(QHostAddress("127.0.0.1"), redirectUriPort, this); // Doens't work either...

This change

• ...goes against https://tools.ietf.org/html/rfc8252#section-8.3 which specifically says that using "localhost" is NOT RECOMMENDED
• ...reversed the fix for QTBUG-67528
• ...prevents authentication from succeeding when the server is only configured to accept "127.0.0.1" (for example, Google's OAuth2 server will reply with "Error 400: redirect_uri_mismatch")