ci: fail the pytest job when an integration cannot be imported

[lesnik512]

Summary

Follow-up to #258, which added REQUIRE_INTEGRATIONS and set it only in the floors job. The pytest job also installs every integration (just install runs uv sync --all-extras, and the dev group has litestar and faststream[nats]). That means a failed import there would also skip a whole integration suite and the job would stay green. This matters most on the daily scheduled run: it resolves the newest releases, so it is where a new faststream, pydantic or litestar release that breaks the import would show up first.

Changes

• The pytest job sets REQUIRE_INTEGRATIONS=1 on its test step, the same as the floors job.

Coverage is unaffected: import_or_skip is a single expression, so the line is covered either way.

Checklist

• Lint and format pass (ruff): no Python changed
• Type check passes (mypy and pyrefly): no Python changed
• Tests pass and new behavior is covered: both matrix variants (faststream<0.6.0, faststream>=0.6.0) replayed locally on 3.12 with the variable set: 458 passed, 0 skipped, coverage 100%
• Build succeeds (uv build) if packaging or build config changed: not applicable
• Docs updated if behavior or public API changed: not applicable
• Repo metadata stays consistent across the three surfaces: not applicable

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

Flag	Coverage Δ
unittests	100.00% <ø> (ø)

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