fix(oidc): return registration_client_uri in PUT and GET dynamic client responses

The OIDC Dynamic Client Registration PUT and GET endpoints do not
include registration_client_uri in their responses, violating the
OpenID Connect Dynamic Client Registration 1.0 specification.

The POST (create) endpoint correctly sets RegistrationClientURI,
but the PUT (update) and GET (read) endpoints omit it.

Set RegistrationClientURI before writing the response in both
setOidcDynamicClient and getOidcDynamicClient, matching the
create handler's behavior.

Fixes #4084

Author: Yanhu007

client/handler.go

@@ -384,6 +384,8 @@ func (h *Handler) setOidcDynamicClient(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	c.RegistrationClientURI = urlx.AppendPaths(h.r.Config().PublicURL(r.Context()), DynClientsHandlerPath, url.PathEscape(c.GetID())).String()
+
 	h.r.Writer().Write(w, r, &c)
 }
 
@@ -666,6 +668,7 @@ func (h *Handler) getOidcDynamicClient(w http.ResponseWriter, r *http.Request) {
 
 	c.Secret = ""
 	c.Metadata = nil
+	c.RegistrationClientURI = urlx.AppendPaths(h.r.Config().PublicURL(r.Context()), DynClientsHandlerPath, url.PathEscape(c.GetID())).String()
 	h.r.Writer().Write(w, r, c)
 }