Skip SpatiaLite tests when using PROJ v6

[ajcvickers]

Split off from #22138.

The released version doesn't work and the fix doesn't seem like it's going to be released anytime soon.

Note: see test issue in #27662. If we don't add support in 7.0, then consider adding a check and throwing a nice exception. Also consider adding a check in the tests to skip these tests if 5.0 is installed.

[bricelam]

So... our current implementation does work with SpatiaLite 5. You just need to work around the segfault by using libsqlite3 instead of e_sqlite3 (the default) or SQLCipher. I don't think we should block it at the product level.

But we can try to detect this in our tests and skip running.

[ajcvickers]

MQ for test part.