ui: only show lang-select when multi lang detected

packages/ui-default/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@hydrooj/ui-default",
-  "version": "4.34.16",
+  "version": "4.34.17",
   "author": "undefined <i@undefined.moe>",
   "license": "AGPL-3.0",
   "main": "hydro.js",

packages/ui-default/templates/problem_detail.html

@@ -75,7 +75,7 @@
         <div class="section__header non-scratchpad--hide">
           <h1 class="section__title">{{ pdoc.title }}</h1>
         </div>
-        {% if pdoc.content|contentLang|length %}
+        {% if pdoc.content|contentLang|length > 1 %}
         <div class="section__tab-container">
           <div class="section__tab-header-wrapper">
             <ul class="section__tab-header flex-row">