core: fix value type

packages/hydrooj/package.json

@@ -1,6 +1,6 @@
 {
     "name": "hydrooj",
-    "version": "3.11.11",
+    "version": "3.11.12",
     "bin": "bin/hydrooj.js",
     "main": "src/loader",
     "module": "src/loader",

packages/hydrooj/src/handler/contest.ts

@@ -208,7 +208,7 @@ export class ContestScoreboardDownloadHandler extends Handler {
     async get(domainId: string, tid: ObjectID, ext: string, ignoreLock = false) {
         await this.limitRate('scoreboard_download', 120, 3);
         const getContent = {
-            csv: async (rows) => `\uFEFF${rows.map((c) => (c.map((i) => i.value?.replace(/\n/g, ' ')).join(','))).join('\n')}`,
+            csv: async (rows) => `\uFEFF${rows.map((c) => (c.map((i) => i.value?.toString().replace(/\n/g, ' ')).join(','))).join('\n')}`,
             html: (rows, tdoc) => this.renderHTML('contest_scoreboard_download_html.html', { rows, tdoc }),
         };
         const tdoc = await contest.get(domainId, tid);