Acceptance test to cover all options in cat/course management work by default

With MDL-42609 a change landed so, by default, the management UI shows the "default category" courses (previously it defaulted to list of categories, if I'm not wrong).

So, right now, that default management page shows the list of courses in the "default category" (usually Miscellaneous). And we need to verify that all the options against that list (mainly sorting) are working ok.

Note the there are already a bunch of acceptance tests covering ordering (lots more were added with MDL-45847). But all them perform tests with some category picked.

We need to ensure everything works without picking any category (that should be 100% equivalent to picking the default category).

So that is it. Something to add to have that new default behavior covered.

Ciao