CI: Address flaky unit tests
Noticed `test_basic_series_frame_alignment` and `test_raw_roundtrip` can occasitionally fail in the CI. Marking as xfail strict=False and clearing the clipboard respectively
pandas/tests/io/test_clipboard.py:426:12: W1510: Using subprocess.run without explicitly set `check` is not recommended. (subprocess-run-check) thanks @mroeschke 