reporter: BTC header submission to Babylon stalls if it passes verification

[vitsalis]

Description

Note: This issue happens if we bootstrap btcd from height 0 along with the vigilante. If btcd already contains headers then the issue of #25 happens.

In this case, the BTC header that is submitted to Babylon passes all checks and the transaction is broadcast. However, the vigilante stalls while (I suppose) it is awaiting for a response. More specifically, the log that is generated here never appears. If a panic is added in its place, then the application does not panic.

Logs:

INFO[2022-09-10T11:18:05+08:00] Successfully loaded config file at .testnet/vigilante/vigilante.yml  module=config
INFO[2022-09-10T11:18:05+08:00] Successfully created the BTC client and connected to the BTC server  module=btcclient
INFO[2022-09-10T11:18:05+08:00] Successfully subscribed to newly connected/disconnected blocks from BTC  module=btcclient
DEBU[2022-09-10T11:18:05+08:00] Babylon key directory: .testnet/node0/babylond  module=babylonclient
DEBU[2022-09-10T11:18:05+08:00] All Babylon addresses: map[node0:bbn1pykpd3wuagxaltxwdaaz4l5ert3vzajddufj7w]  module=babylonclient
INFO[2022-09-10T11:18:05+08:00] Successfully created the Babylon client       module=babylonclient
INFO[2022-09-10T11:18:05+08:00] Successfully generated TLS certificates for the RPC server  module=rpcserver
INFO[2022-09-10T11:18:05+08:00] BTCCheckpoint parameters: (k, w) = (10, 100)  module=reporter
INFO[2022-09-10T11:18:05+08:00] BTC latest block hash and height: (683e86bd5c6d110d91b94b97137ba6bfe02dbbdb8e3dff722a669b5d69d77af6, 0)  module=reporter
INFO[2022-09-10T11:18:05+08:00] BBN header chain latest block hash and height: (683e86bd5c6d110d91b94b97137ba6bfe02dbbdb8e3dff722a669b5d69d77af6, 0)  module=reporter
INFO[2022-09-10T11:18:05+08:00] Successfully started the vigilant reporter    module=reporter
INFO[2022-09-10T11:18:05+08:00] Successfully started the GRPC server at 127.0.0.1:8080  module=rpcserver
INFO[2022-09-10T11:18:05+08:00] Successfully started Prometheus metrics server at localhost:2112  module=metrics
INFO[2022-09-10T11:18:05+08:00] epoching params: epoch_interval:10            module=cmd
DEBU[2022-09-10T11:18:08+08:00] Block 09bfc59c3367f2520b48ef1703c5b25cd678d951d1eeafa7e27b1549fdaacd30 at height 1 has been connected at time 2022-09-10 11:18:08 +0800 WITA  module=btcclient
INFO[2022-09-10T11:18:08+08:00] Start handling block 09bfc59c3367f2520b48ef1703c5b25cd678d951d1eeafa7e27b1549fdaacd30 from BTC client  module=reporter
DEBU[2022-09-10T11:18:08+08:00] signer: 092C16C5DCEA0DDFACCE6F7A2AFE991AE2C1764D, headerHex: 00000020f67ad7695d9b662a72ff3d8edbbb2de0bfa67b13974bb9910d116d5cbd863e68875321d07ecf021b8b7503c9ffb731c4b1a5418a9fd8bd808e53b5e6c8cb69b1f0011c63ffff7f2002000000  module=reporter

<Nothing after that>

Steps to reproduce

Assumes that #24 is fixed.

Run the instructions on the README to setup a Babylon instance, a clean BTC simnet (starting from height 0), and the vigilante. Then run the vigilante in reporter mode according to the instructions.

@SebastianElvis @gusin13 thoughts?