Add better error handling when Discord messages go wrong

[EricPickup]

Whenever we create an event we make an announcement to the Discord server with the details of the event.

Discord has some weird limitations (the most important one being text size). We send event descriptions from the site to Discord and a lot of times the descriptions were too big and the website returned an error when creating the event because of this. The error has no details though so someone posting an event who isn't me and doesn't know the limitations will have no idea what's going wrong.

We should raise an error if the Discord message doesn't go through and tell them what went wrong. Right now if something goes wrong, the event is still created (since we do that first) and then it tries to send a message and returns an error.

[amanpatel123]

Will take a look and let you know of any updates