tests(dashboard): [#306] added test coverage for the metric detail route

[AaronProbha18]

Fixes: #306

Changes

• Added TestSessionMetricDetailPage to tests/unit/dashboard/test_api.py, covering the session_metric_detail route added in the prior sub-issue.
• 200 + content coverage: valid metric URL returns 200 (test_returns_200_for_known_metric), and the embedded metrics JSON blob is scoped to just that metric's points rather than the full unfiltered list (test_content_includes_correct_point_values), plus a breadcrumb-link check back to the parent session (test_content_includes_breadcrumb_to_session).
• 404 coverage: unknown metric name, unknown session, unknown project, and a metric name requested on a session with zero recorded metrics (test_returns_404_for_unknown_metric, test_returns_404_for_unknown_session, test_returns_404_for_unknown_project, test_returns_404_for_metric_on_session_with_no_metrics).
• Auth coverage: unauthenticated request to the detail route redirects to /connect (test_requires_authentication), consistent with the parent session route's existing behavior.
• Link-generation coverage: the session page's Graphs tab renders "View details" links to all three metrics (test_session_page_links_to_metric_detail), and a regression check that a session with no <metric> data at all still renders those links without erroring (test_session_page_without_metrics_does_not_break).

Notes

• Updated tests to ensure the session ID format regex supports both adjectives and nouns.(fix commit)
• Corrected the style in fenn/reproducibility.py to pass ruff format check.