fix: parse post content before sending notification

[cryptoethic]

Resolves issue I have created on NodeBB repo: NodeBB/NodeBB#8358

Parse post content before sending notification

[julianlam]

This would cause issues in the notifications themselves (in NodeBB), as they're not meant to take raw html.

There might be a different hook you can use for markdown parsing for emails only ..

[cryptoethic]

Okay. What about SocketHelpers.sendNotificationToPostOwner from core src/socket.io/helpers.js

It is from where I took inspiration

[cryptoethic]

I believe it can be attached to filter:email.params (checking if type of notification type is mention and then replacing body with post.parsePost)

But what about other notifications types that parse post content before firing. I haven't noticed them working incorrectly.