ci(backend): Add poetry.lock check

[Pwuts]

• Resolves Ensure backend/poetry.lock is always compatible/up-to-date with autogpt_libs dependencies #8884

We need to prevent breaking updates to dependency version requirements of autogpt_libs.
autogpt_libs/pytroject.toml and backend/poetry.lock are loosely coupled, and to ensure they stay in sync we need an extra check.

For now I'm also reverting the breaking update of #8787, otherwise this added CI check will immediately fail.

Changes

• ci(backend): Add poetry.lock check
• Revert "build(deps): bump pydantic from 2.9.2 to 2.10.2 in /autogpt_platform/autogpt_libs in the production-dependencies group across 1 directory (build(deps): bump pydantic from 2.9.2 to 2.10.2 in /autogpt_platform/autogpt_libs in the production-dependencies group across 1 directory #8787)"

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