Remove LC_COLLATE test from CI tests

[nyurik]

See #35 -- CI tests break when used with PG 16 because per release notes:

Remove read-only server variables lc_collate and lc_ctype (Peter Eisentraut)
Collations and locales can vary between databases so having them as read-only server variables was unhelpful.

[ikalnytskyi]

I don't think removing the test is what we should do. The point of the test is to check default configuration of the PostgreSQL server from a user point of view. There's a big difference between having locale being set to C or C.UTF-8 or en_US.UTF-8 or something else. It does affect sort order (i.e. ORDER BY) of strings and may lead to flaky tests if we don't control it.

It goes without saying that I'd expect consumers to set proper collation on per-column basis in their database schema. However, as a maintainer of general purpose action, I have to come up with a default that just works, but most importantly, works the same regardless of the runner we're using.

I wasn't aware that LC_COLLATE and LC_CTYPE are gone now, yet I'd expect some kind of default value should exist in the configuration somewhere. Let me research a bit before making decision on how to proceed.