test(consistent): curate DPA3 descriptor matrix (#5390)

Problem
- `source/tests/consistent/descriptor/test_dpa3.py` still used a
Cartesian-product parameter matrix, so applying the curated-case
approach from #5378 to DPA3 required the same cleanup.
- The full product made the coverage intent harder to review and mixed
many independent toggles into opaque combinations.

Change
- Replace the Cartesian-product parameterization in the DPA3 consistent
test with explicit curated case tuples.
- Split the curated cases for the descriptor behavior test and
descriptor API test so each keeps the relevant edge toggles while
remaining reviewable.
- Keep one mixed high-risk path to preserve interaction coverage across
the repflow-related switches.

Notes
- Local environment in this worktree does not currently have a ready
pytest installation, so I only ran `git diff --check` as a quick sanity
check here.
- This follows the same curated-matrix testing idea used in #5378, but
applies it to the DPA3 descriptor consistent tests.

Authored by OpenClaw (model: gpt-5.4)


<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **Tests**
* Reworked DPA3 tests to use curated, case-driven parameterization from
centralized case builders for clearer, more maintainable scenarios.
* Descriptor API tests switched from an exhaustive matrix to curated
scenarios, altering coverage and some statistical settings.
* Test payloads and unpacking updated to surface an additional
descriptor parameter used by the tests.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Author: njzjz-bot