Function zebra_state::service::finalized_state::disk_format::upgrade::add_subtrees::quick_check_sapling_subtrees

fn quick_check_sapling_subtrees(db: &ZebraDb) -> Result<(), &'static str>

Quickly check that the first calculated sapling subtree is correct.

This allows us to fail the upgrade quickly in tests and during development, rather than waiting ~20 minutes to see if it failed.

Returns an error if a note commitment subtree is missing or incorrect.