fix: oidc: don't wish for a refresh token

src/pages/api/auth/oauth/oidc.ts

@@ -60,14 +60,13 @@ async function handler({ code, host, state }: OAuthQuery, _logger: Logger): Prom
 
   const json = await res.json();
   if (!json.access_token) return { error: 'No access token in response' };
-  if (!json.refresh_token) return { error: 'No refresh token in response' };
 
   const userJson = await oidcAuth.user(json.access_token, config.oauth.oidc.userinfoUrl!);
   if (!userJson) return { error: 'Failed to fetch user' };
 
   return {
     access_token: json.access_token,
-    refresh_token: json.refresh_token,
+    refresh_token: json.refresh_token || null,
     username: userJson.preferred_username,
     user_id: userJson.sub,
   };