psa: test: Fix truncation of message by snprintf

We had only allocated 40 bytes for printing into, but we wanted to print 46
bytes. Update the buffer to be 47 bytes, which is large enough to hold what
we want to print plus a terminating null byte.

tests/suites/test_suite_psa_crypto.function

@@ -631,7 +631,7 @@ static int exported_key_sanity_check( psa_key_type_t type, size_t bits,
         else
 #endif /* MBEDTLS_ECP_C */
         {
-            char message[40];
+            char message[47];
             mbedtls_snprintf( message, sizeof( message ),
                               "No sanity check for public key type=0x%08lx",
                               (unsigned long) type );