Remove modmail_guild_id from env examples (#3281)

* Update .env.example

The removal of `modmail_guild_id` since its causing more confusion to people then it helps them. Features relying on this never were made.

Signed-off-by: lorenzo132 <50767078+lorenzo132@users.noreply.github.com>

* Update app.json

---------

Signed-off-by: lorenzo132 <50767078+lorenzo132@users.noreply.github.com>

Author: lorenzo132

.env.example

@@ -1,6 +1,5 @@
 TOKEN=MyBotToken
 LOG_URL=https://logviewername.herokuapp.com/
 GUILD_ID=1234567890
-MODMAIL_GUILD_ID=1234567890
 OWNERS=Owner1ID,Owner2ID,Owner3ID
 CONNECTION_URI=mongodb+srv://mongodburi

app.json

@@ -11,10 +11,6 @@
             "description": "The id for the server you are hosting this bot for.",
             "required": true
         },
-        "MODMAIL_GUILD_ID": {
-            "description": "The ID of the discord server where the threads channels should be created (receiving server). Default to GUILD_ID.",
-            "required": false
-        },
         "OWNERS": {
             "description": "Comma separated user IDs of people that are allowed to use owner only commands. (eval).",
             "required": true
@@ -40,4 +36,4 @@
             "required": false
         }
     }
-}
+}