Extend sleep in test_pandas (#8438)

[juliangilbey]

Closes #8438

• Tests added / passed

Now passes test_pandas

• Passes pre-commit run --all-files

[GPUtester]

Can one of the admins verify this patch?

Admins can comment ok to test to allow this one PR to run or add to allowlist to allow all future PRs from the same author to run.

[github-actions]

Unit Test Results

See test report for an extended history of previous test failures. This is useful for diagnosing flaky tests.

    27 files  ±0      27 suites  ±0   9h 50m 42s ⏱️ + 11m 43s
 3 951 tests ±0   3 839 ✅  - 2    109 💤 ±0  3 ❌ +2 
49 696 runs  ±0  47 404 ✅  - 2  2 289 💤 ±0  3 ❌ +2 

For more details on these failures, see this check.

Results for commit 97af828. ± Comparison against base commit 81774d4.

[hendrikmakait]

@juliangilbey: Thanks for your contribution, and nice detective work tracking this one down!