fix: always run poetry install to prevent missing pytest from stale cache

[LanusseMorais]

Summary

• Integration tests failing on PR chore: 🐝 Update SDK - Generate 3.0.1 #26 with Command not found: pytest
• The Install dependencies step was conditional on cache miss, but the cached .venv was stale (missing pytest)
• Removed the if: cache-hit != 'true' condition so poetry install always runs
• When cache is valid, poetry install is a fast no-op (just verifies dependencies)

Test plan

• This fix should unblock the integration tests on PR chore: 🐝 Update SDK - Generate 3.0.1 #26

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Note

Low Risk
Low risk CI-only change that may slightly increase job time but reduces flakiness from stale cached virtualenvs.

Overview
Integration test CI now always runs poetry install --with dev even when the .venv cache is restored, preventing failures from stale caches missing dev tools like pytest.

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