core: remove problem_send

packages/ui-default/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@hydrooj/ui-default",
-  "version": "4.8.46",
+  "version": "4.9.0",
   "author": "undefined <i@undefined.moe>",
   "license": "AGPL-3.0",
   "main": "hydro.js",

packages/ui-default/templates/problem_detail.html

@@ -5,7 +5,6 @@
 {{ set(UiContext, {
   problemId: pdoc.pid|default(pdoc.docId),
   problemNumId: pdoc.docId,
-  postCopyUrl: url('problem_send'),
   postPretestUrl: url('problem_pretest', pid=pdoc.docId),
   codeLang: handler.user.codeLang,
   codeTemplate: handler.user.codeTemplate,