[chronik] add electrum method blockchain.transaction.get_height

Summary:
As per title.
Also refactor some boilerplate code into TxId::TryFrom<serde_json::Value>

Depends on D17347
Ref T3598

Test Plan: ninja check-functional

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Subscribers: Fabien

Maniphest Tasks: T3598

Differential Revision: https://reviews.bitcoinabc.org/D17356