validate_blockchain_rid
Checks whether the blockchain RID has the correct size
Throws "INVALID BRID"
if the RID's length is not 32 bytes.
Should be used inside other functions, and the descriptor
parameter should be passed in a way that the error message is understood by the end users.
Example: validate_blockchain_rid(x"", "Chain X's RID")
will throw this error: "INVALID BRID: Chain X's RID cannot be empty"
Parameters
blockchain_rid
The RID to check
descriptor
the name of the parameter for nicer error printing