[CONSENSUS] Add Quorum Certificate verification tests

[gokutheengineer]

Objective

Nodes perform Quorum Certificate (QC) verification when committing a block in the consensus process, and for validating blocks received via state synchronization. The objective of this issue is to implement QC verification tests.

Goals

• Implement QC verification tests in the consensus e2e_tests/hotstuff_test.go
• Add more QC verification tests to the e2e_tests/hotstuff_test.go.

Deliverable

• QC verification tests implementation.
• Ensuring QC verification process is correct with extensive tests.

Non-goals / Non-deliverables

• Change business logic.

General issue deliverables

• Update the appropriate CHANGELOG(s)
• Update any relevant local/global README(s)
• Update relevant source code tree explanations
• Add or update any relevant or supporting mermaid diagrams

Testing Methodology

• Task specific tests or benchmarks: make ...
• New tests or benchmarks: make ...
• All tests: make test_all
• LocalNet: verify a LocalNet is still functioning correctly by following the instructions at docs/development/README.md

---

Creator: @gokutheengineer
Co-Owners: @Olshansk

[Olshansk]

@gokutheengineer Could you please link to the place in the codebase where the placeholders for the business logic and tests currently live?