database: use standard PostgreSQL syntax for license removal

[justinclift]

This switches a SQL statement from using jsquery syntax, to standard PostgreSQL syntax. It's needed because the existing jsquery syntax doesn't seem to work correctly with newer versions of jsquery.

While we could just update the query to use newer jsquery syntax, we might as well take this opportunity to reduce our dependencies by using standard PostgreSQL syntax instead.

[justinclift]

At first it looked like extending the Cypress waiting time made a difference, as the test with that included passed immediately.

But it seems like that's co-incidence more than anything, as the subsequent runs (with the commit message cleaned up a bit) are all failing again.

It seems like a problem with GitHub Actions itself, as this PR passes fine on my system ok and occasionally passes ok on GitHub Actions. So "unreliable GitHub Actions" is where things seem to be.

I'm seriously glad we don't have to pay GitHub for CI runs, as if it was a paid thing we'd have moved to an alternative.