[CO] fix pipeline futures

[zekun000]

This commit properly sets parent futures when the ordered blocks have more than one block.

Description

How Has This Been Tested?

Key Areas to Review

Type of Change

• New feature
• Bug fix
• Breaking change
• Performance improvement
• Refactoring
• Dependency update
• Documentation update
• Tests

Which Components or Systems Does This Change Impact?

• Validator Node
• Full Node (API, Indexer, etc.)
• Move/Aptos Virtual Machine
• Aptos Framework
• Aptos CLI/SDK
• Developer Infrastructure
• Move Compiler
• Other (specify)

Checklist

• I have read and followed the CONTRIBUTING doc
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I identified and added all stakeholders and component owners affected by this change as reviewers
• I tested both happy and unhappy path of the functionality
• I have made corresponding changes to the documentation

[trunk-io]

⏱️ 15m total CI duration on this PR

Job	Cumulative Duration	Recent Runs
check-dynamic-deps	5m	🟩 🟩
test-target-determinator	4m	🟩
rust-cargo-deny	3m	⬜ 🟩
general-lints	57s	🟩 🟩
semgrep/ci	42s	🟩 🟩
file_change_determinator	25s	🟩 🟩
file_change_determinator	10s	🟩
permission-check	6s	🟩 🟩
permission-check	5s	🟩 🟩
permission-check	4s	🟩
determine-docker-build-metadata	1s	🟩

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