Bounty 24 was created as a test by the W3F Tech Ed team.  This referendum seeks to remove it as part of good chain housekeeping.

Cancel a proposed or active bounty. All the funds will be sent to treasury and
the curator deposit will be unreserved if possible.

Only `T::RejectOrigin` is able to cancel a bounty.

- `bounty_id`: Bounty ID to cancel.

## Complexity
- O(1).

- There is a test called Bounty 24 created by the W3F Tech Ed team.
- A referendum is being held to remove Bounty 24.
- This is done to keep the chain organized and clean.
- The referendum is about getting rid of something that was created for testing.
- It is important to have good chain housekeeping.

#282 Cleanup on aisle 24 - Tech Ed test bounty