remove unnecessary under bar

resource/locales/ja_JP/admin/admin.json

@@ -252,7 +252,7 @@
   },
   "slack_integration": {
     "official_bot": "Official bot",
-    "custom_bot_without_proxy": "Custom_bot_without_proxy",
+    "custom_bot_without_proxy": "Custom bot without proxy",
     "custom_bot_with_proxy": "Custom bot without proxy",
     "selecting_bot_types": {
       "for_beginners": "- 初心者向け -",