Get raw blockchain block header
block ID: (workchain,shard,seqno,root_hash,file_hash)
"(-1,8000000000000000,4234234,3E575DAB1D25...90D8,47192E5C46C...BB29)"
raw blockchain block header
0
"131D0C65055F04E9C19D687B51BC70F952FD9CA6F02C2801D3B89964A779DF85"