fix: update python script inside account_changes adding index_in_block migration

[telezhnaya]

sqlalchemy is too smart, it decides whether we need to commit changes based on first line of raw sql statement. https://stackoverflow.com/questions/45347565/executing-multiple-statements-with-postgresql-via-sqlalchemy-does-not-persist-ch It was a script from Bohdan https://github.com/near/near-indexer-for-explorer/pull/99#issuecomment-838871700 Bohdan's update started from UPDATE and everything worked. Mine started from WITH and sqlalchemy decided not to commit anything because of that. We lost some logging, but at least it works

It runs now on 34.141.101.9 for testnet