ENG-469 Fix: prefer headers for block info

[piotr-roslaniec]

Summary

• refers to ENG-469 Irritating error transaction type not supported keep-core#3841
• add ChainReader.HeaderByNumber and use it in block counter to avoid decoding full blocks
• adapt Ethereum adapter + tests to fetch headers instead of blocks
• use headers for mining waiter base fee lookup (fixes nil mock panic and avoids unsupported tx types)
• keep generated async promise code tracked for passing tests

Testing

• go test ./...

[linear]

ENG-469 Fix `transaction type not supported`