test: migrate workspace members tests to containers

[escape0707]

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Summary

• Migrates SQL-backed workspace member controller tests from mock-based unit tests to Testcontainers-backed integration tests.
• Keeps non-DB invitation, permission, and token-validation unit coverage in place.
• Supersedes inactive PR test: migrate workspace members mock tests to testcontainers #35203, removes its unrelated JavaScript integration-test deletion, and addresses review feedback by using real DB/Redis behavior for role updates and owner-transfer token handling.

Part of #32454

Screenshots

N/A

Checklist

• This change requires a documentation update, included: Dify Document
• I understand that this PR may be closed in case there was no previous discussion or issues. (This doesn't apply to typos!)
• I've added a test for each change that was introduced, and I tried as much as possible to make a single atomic change.
• I've updated the documentation accordingly.
• I ran make lint && make type-check (backend) and cd web && pnpm exec vp staged (frontend) to appease the lint gods

Validation:

• uv run --project api ruff check api/tests/test_containers_integration_tests/controllers/console/workspace/test_members.py api/tests/unit_tests/controllers/console/workspace/test_members.py
• uv run --project api pytest api/tests/unit_tests/controllers/console/workspace/test_members.py - 20 passed
• DOCKER_HOST=unix:///run/user/1000/podman/podman.sock uv run --project api pytest api/tests/test_containers_integration_tests/controllers/console/workspace/test_members.py - 10 passed

[github-actions]

Pyrefly Type Coverage

Metric	Base	PR	Delta
Type coverage	45.79%	45.77%	-0.02%
Strict coverage	45.31%	45.29%	-0.02%
Typed symbols	24,531	24,535	+4
Untyped symbols	29,352	29,380	+28
Modules	2740	2741	+1