CI: xfail strict=True TestClipboard.test_raw_roundtrip in a CI environment
Unfortunately clearing out the clipboard in the CI didn't fix the flaky failures. Setting `strict=False` if in our CI

https://github.com/pandas-dev/pandas/actions/runs/4433507399/jobs/7778613334
thx @mroeschke  Is the clipboard stuff commonly used?  If we're effectively not testing it on the CI, might be worth deprecating support? No clue if this is actually used.  I've used it a few times; can be convenient when copy/pasting tables online. But 100% think it should be spun off into it's own IO community project