Remove global electrum workarounds made for electrs

[nkuba]

To support Electrs we had to add couple of workarounds in GetTransaction and GetTransactionConfirmations methods due to Blockstream/electrs#36.

Example: 3db34f0

Those workarounds are not necessary for other servers we integrate with like ElectrumX and Fulcrum. Having the workarounds generally applied makes the flow complicated and complicated.

We should use the workaround only for Electrs and use the functions exposed by other servers directly.