Cancelling Custom Bounty Requires Github URL

[GTChase]

Steps To Reproduce Steps to reproduce the behavior:

1. Create a custom bounty successfully
2. Cancel bounty

Observed behavior Cancelling a custom bounty requires a github URL, but the custom bounties arent tied to github

Expected behavior Cancelling custom bounty shouldnt require github related information

Note: This change should only take place for custom bounties.. bounties created off of github issues should remained unchanged