Stick to some new props in API v2

[vbaranov]

In continuation to #2374 and #2429 issues, I am asking to stick with alternatives for 2 more renamed props in API v2:

old prop name	new prop name	status	comment
blob_tx_count	blob_transaction_count	✅	was changed before 😯
tx_burnt_fee	transaction_burnt_fee	✅

New props are available in backend 6.10.1.