zebra-test: fix Orchard ZSA workflow vectors after correcting hashBlockCommitments

zebra-test/src/vectors/orchard-zsa-workflow-block-1.txt had an all-zero
hashBlockCommitments (ZIP-244) field. Updating it changes the block hash and
chain history tree roots, so blocks 2–4 required updated hashBlockCommitments as
well, and blocks 2–5 required previous_block_hash relinking.

This regenerates the workflow block *.txt vectors so the orchard_zsa workflow
test passes without bypasses.

Author: dmidem