fix: make the nightly hypothesis failure alarm able to file issues - #4274

Summary

Fixes #4273. The nightly hypothesis workflow's failure-reporting step has never been able to file its "Nightly Hypothesis tests failed" issue. Three small changes make it work:

• Write the report log the action reads: pytest-reportlog added to the test dependency group and --report-log passed via PYTEST_ADDOPTS on the test step (the reporting step was adapted from xarray, where the pytest invocation carries this flag).
• Grant the job issues: write: the workflow-level contents: read from Limit privilege escalation and token theft in workflows #3742 leaves the token unable to create issues; this uses the same job-level pattern as links.yml and issue-metrics.yml, whose auto-issues do land.
• Use the existing automated issue label: the configured topic-hypothesis label doesn't exist, and gh issue new errors on unknown labels rather than creating them. automated issue is what the Link Checker reports already use.

Demonstrated on a fork at this exact configuration: a forced nightly-style failure auto-files the issue (run → auto-created issue, label applied), and the suite stays green with reportlog enabled (run).

Prepared with Claude (AI) and submitted at my direction, per the invitation on #4273.

For reviewers

Two choices you may want differently: a dedicated topic-hypothesis label instead of reusing automated issue (it would need creating before merge), and whether the flag should live in the run-hypothesis hatch script rather than PYTEST_ADDOPTS on the workflow step.

Author attestation

• I am a human, these are my changes, and I have reviewed and understood every change and can explain why each is correct.

TODO

• GitHub Actions have all passed
• Unit tests / docstrings / user-guide docs / changes/ entry: n/a — CI-only change (same as fix: use hatch's default env so the uv installer is inherited #4023)