core: 修复avatar参数错误导致页面渲染失败的问题

packages/hydrooj/package.json

@@ -1,6 +1,6 @@
 {
     "name": "hydrooj",
-    "version": "2.27.4",
+    "version": "2.27.5",
     "bin": "bin/hydrooj.js",
     "main": "dist/loader.js",
     "typings": "dist/loader.d.ts",

packages/hydrooj/src/lib/avatar.ts

@@ -4,7 +4,7 @@ type AvatarProvider = (src: string, size: number) => string;
 
 export const providers: Record<string, AvatarProvider> = {
     gravatar: (email, size) => `//gravatar.loli.net/avatar/${md5((email || '').toString().trim().toLowerCase())}?d=mm&s=${size || 32}`,
-    qq: (id) => `//q1.qlogo.cn/g?b=qq&nk=${/(\d+)/g.exec(id)[1]}&s=640`,
+    qq: (id) => `//q1.qlogo.cn/g?b=qq&nk=${(/(\d+)/g.exec(id) || ['', ''])[1]}&s=640`,
     github: (id, size) => `//github.com/${id}.png?size=${Math.min(size, 460)}`,
 };