TST: Fix CI failures (don't xfail postgresql / don't xfail for pyarrow=16)
Using `tm.assert_produces_warning` for the first test gives:
```
AssertionError: Warning not set with correct stacklevel
```
It seems the stacklevel is set incorrectly and should be changed (see #55591), I just temporarily fixed it by using `pytest.mark.filterwarnings`
pre-commit.ci autofix `xarray` just released a new version which seems to be breaking some tests. I will take a look at it tomorrow if no one else fixes it. Thanks @Aloqeely 