library/tests: replace md_psa.h with psa_util.h as include file for MD conversion

Signed-off-by: Valerio Setti <valerio.setti@nordicsemi.no>
diff --git a/library/ssl_tls13_client.c b/library/ssl_tls13_client.c
index ae11364..ffaffe9 100644
--- a/library/ssl_tls13_client.c
+++ b/library/ssl_tls13_client.c
@@ -19,7 +19,7 @@
 #include "ssl_client.h"
 #include "ssl_tls13_keys.h"
 #include "ssl_debug_helpers.h"
-#include "md_psa.h"
+#include "mbedtls/psa_util.h"
 
 #if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_EPHEMERAL_ENABLED)
 /* Define a local translating function to save code size by not using too many