test: add batch_deduct event ordering and revert tests

[karanjakevin39-collab]

• batch_deduct_events_fire_in_input_order: asserts deduct events are
  emitted in the same sequence as the input Vec items
• batch_deduct_events_carry_correct_running_balance: asserts each event
  carries the per-item running balance (not the final balance)
• batch_deduct_max_deduct_violation_at_index_0_reverts_all: violation
  at position 0 reverts the whole batch, no events emitted
• batch_deduct_max_deduct_violation_at_middle_index_reverts_all: same
  for a violation at a middle index
• batch_deduct_max_deduct_violation_at_last_index_reverts_all: same
  for a violation at the last index

All 158 tests pass. Closes #346

[drips-wave]

@karanjakevin39-collab Great news! 🎉 Based on an automated assessment of this PR, the linked Wave issue(s) no longer count against your application limits.

You can now already apply to more issues while waiting for a review of this PR. Keep up the great work! 🚀

Learn more about application limits