fix(auth): support for oauth2 relative url (#6546)

* Handle relative urls for oauth authorization

The full URL is computed based on the current selected server
if a relative URL is used as authorizationUrl
or tokenUrl


Co-authored-by: Eliot Berriot <contact@eliotberriot.com>

src/core/plugins/auth/actions.js

@@ -174,8 +174,8 @@ export const authorizeRequest = ( data ) => ( { fn, getConfigs, authActions, err
   let parsedUrl
 
   if (specSelectors.isOAS3()) {
-    const server = oas3Selectors.selectedServer()
-    parsedUrl = parseUrl(url, oas3Selectors.serverEffectiveValue({ server }), true)
+    let finalServerUrl = oas3Selectors.serverEffectiveValue(oas3Selectors.selectedServer())
+    parsedUrl = parseUrl(url, finalServerUrl, true)
   } else {
     parsedUrl = parseUrl(url, specSelectors.url(), true)
   }