Changed wording for "Maximum Allowed Message Size"

Previously this wasn't too clear that it was for characters rather than the size for if you wanted to upload a larger file. Changed this to be more obvious by mentioning 'characters'. User-friendliness. :- )

packages/rocketchat-i18n/i18n/en.i18n.json

@@ -1194,7 +1194,7 @@
   "Message_HideType_ul": "Hide \"User Leave\" messages",
   "Message_KeepHistory": "Keep Per Message Editing History",
   "Message_MaxAll": "Maximum Channel Size for ALL Message",
-  "Message_MaxAllowedSize": "Maximum Allowed Message Size",
+  "Message_MaxAllowedSize": "Maximum Allowed Characters Per Message",
   "Message_pinning": "Message pinning",
   "Message_QuoteChainLimit": "Maximum Number of Chained Quotes",
   "Message_removed": "Message removed",