audius-protocol Fix signature in SDK rewards

Description

Occasionally an attestation signature returned by our services will have less than 64 bytes. When recreating this signature logic, I didn't realize that meant it could have 63 1/2 bytes 😝

Using Buffer.alloc() to ensure 64 bytes was stripping the last half-byte off and pushing everything a half byte. Eg.

d405b277dc948f97d7b7db8648cb16590d66084ba49642fedb08380ce5027a95d0a895287a3331332e7ad13daba87eed5c70820a19ca2eb6cc0ea1eb4695ba4

would become 00d405b277dc948f97d7b7db8648cb16590d66084ba49642fedb08380ce5027a95d0a895287a3331332e7ad13daba87eed5c70820a19ca2eb6cc0ea1eb4695ba (note the two prepended 0s)

instead of 0d405b277dc948f97d7b7db8648cb16590d66084ba49642fedb08380ce5027a95d0a895287a3331332e7ad13daba87eed5c70820a19ca2eb6cc0ea1eb4695ba4 (note the 4)

That was fun.

While I was at it, I noticed the new cooldown errors from @sddioulde 's changes, and decided the error handling in reportToSentry should add the responses if it can.