The test_measure_time_to_first_review_type_error_path test was passing
but not actually reaching the except TypeError block. The MagicMock
review's submitted_at (a MagicMock, not a datetime) caused
ignore_comment to skip the review as 'pending', so first_review_time
stayed None and the function returned before the TypeError could occur.

Use side_effect to raise TypeError directly from the reviews() call,
which properly exercises the exception handling path.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

…to-first-review-type-error

fix: correct TypeError test to exercise exception handler