Update modulepath test for provider config to skip if not present

Update modulepath test for provider config to skip if not present

If the p_test.so library isn't present, don't run the test

Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/24025)