refactor: remove unused translations

Author: realth000

lib/i18n/zh-CN.i18n.json

@@ -185,8 +185,7 @@
     "behaviorSection": {
       "title": "行为",
       "doublePressExit": {
-        "title": "按两下返回才退出应用",
-        "detail": "避免意外退出app"
+        "title": "按两下返回才退出应用"
       },
       "threadReverseOrder": {
         "title": "倒序浏览帖子",
@@ -1240,4 +1239,4 @@
     "signature": "个人签名",
     "timezone": "时区"
   }
-}
+}

lib/i18n/zh-TW.i18n.json

@@ -184,10 +184,6 @@
     },
     "behaviorSection": {
       "title": "行為",
-      "doublePressExit": {
-        "title": "按兩下返回才退出應用",
-        "detail": "避免意外退出app"
-      },
       "threadReverseOrder": {
         "title": "倒序瀏覽貼文",
         "detail": "貼文裡優先看到最新發布的樓層"
@@ -1240,4 +1236,4 @@
     "signature": "個人簽名",
     "timezone": "時區"
   }
-}
+}