Fix and test pk_copy_from_psa with an unsupported algorithm

Fix mbedtls_pk_copy_from_psa() and mbedtls_pk_copy_public_from_psa() to
still work when the algorithm in the key policy is not an RSA
algorithm (typically PSA_ALG_NONE). Add a dedicated test case and adjust the
test code. Fixes the test case "Copy from PSA: non-exportable -> public, RSA"
when MBEDTLS_PKCS1_V15 is disabled.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/library/pk.c b/library/pk.c
index 7bc1da8..1d85c92 100644
--- a/library/pk.c
+++ b/library/pk.c
@@ -1444,7 +1444,8 @@
 
         if (PSA_ALG_IS_RSA_OAEP(alg_type) || PSA_ALG_IS_RSA_PSS(alg_type)) {
             ret = mbedtls_rsa_set_padding(mbedtls_pk_rsa(*pk), MBEDTLS_RSA_PKCS_V21, md_type);
-        } else {
+        } else if (PSA_ALG_IS_RSA_PKCS1V15_SIGN(alg_type) ||
+                   alg_type == PSA_ALG_RSA_PKCS1V15_CRYPT) {
             ret = mbedtls_rsa_set_padding(mbedtls_pk_rsa(*pk), MBEDTLS_RSA_PKCS_V15, md_type);
         }
         if (ret != 0) {