Support to add custom consensus in conduit

[scholtz]

This is dependant on https://github.com/algorand/go-algorand-sdk/pull/625

Summary

Conduit cannot process any blocks for algorand blockchains with custom consensus. This 5 line PR fixes it.

Test Plan

I tested it manually on aramidmain blockchain.

[scholtz]

for the record in the current official conduit is still the bug that the custom consensus cannot be processed