Add utility function ossl_param_is_empty()

Add utility function ossl_param_is_empty()

Changed all provider implementations that have a set_ctx_params()
to call this function instead of just testing (params == NULL).This
detects the case wherean OSSL_PARAM array contains just a terminator
entry.

Reviewed-by: Richard Levitte <levitte@openssl.org>
Reviewed-by: Tom Cosgrove <tom.cosgrove@arm.com>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/25499)