gh-95291: Use import helper to improve sqlite3 audit tests (GH-95292)

Now the tests are correctly reported as skipped if sqlite3 is not available.
(cherry picked from commit 152eb90311fdf294510b5d077332580ba18c0ee4)

Co-authored-by: Erlend Egeberg Aasland <erlend.aasland@protonmail.com>