Fixed bug that allowed multiple subscriptions to created/edited simultaneously

[DavisPoGo]

If you were in the process of setting up a subscription (or had just viewed you subscription) and then entered a command to start a different subscription, collectors for both will be open and things get a bit confusing. This PR adds a check to see if a command entered during a subscription beings with the bot prefix. If it does, the current subscription will be canceled. Additionally, in this scenario both messages.js and collect_option.js or collect_detail.js would try to delete the same message, resulting in an error. I'm not sure why the try...catch doesn't work, but it wasn't. So I added another check for the bot prefix before collect_option.js or collect_detail.js tries to delete that message.