libmagic now recognizes officedocument.spreadsheetml.sheet

[JulienPalard]

Previously, using for example libmagic1 1:5.30-1+deb9u2:

>>> import magic
>>> magic.Magic(mime=True).from_file('tests/input/xlsx/the_xlsx_no_extension')
'application/octet-stream'

But now (tested on Debian Buster and Bullseye with ligmagic1 1:5.35-4 and libmagic1 1:5.37-5:

>>> import magic
>>> magic.Magic(mime=True).from_file('tests/input/xlsx/the_xlsx_no_extension')
'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet'

In Travis we're using Xenial so we're having libmagic`1:5.25, no issue.

I'd vote for just removing this test, it has not a lot of sense to ensure this is failing.