Improvements and fixes for push notifications (#11507)

* Strip markdown from push notifications

* Revert "Strip markdown from push notifications"

This reverts commit 4741e584c6.

* correctly set type for mention push notifications

* Add unformattedText field to chat messages

* fiix lint errors

* Add check that markdown formatting is stripped from messages

* Add check for markdown formatting in messages.

website/server/libs/inbox/index.js

@@ -23,7 +23,7 @@ export async function sentMessage (sender, receiver, message, translate) {
           { name: getUserInfo(sender, ['name']).name },
           receiver.preferences.language,
         ),
-        message,
+        message: messageSent.unformattedText,
         identifier: 'newPM',
         category: 'newPM',
         payload: { replyTo: sender._id, senderName, message },