Fix pg_hba_file_rules for authentication method cert

For authentication method cert, clientcert=verify-full is implied. But
the pg_hba_file_rules entry would incorrectly show clientcert=verify-ca.

Per bug #17354

Reported-By: Feike Steenbergen
Reviewed-By: Jonathan Katz
Backpatch-through: 12

src/backend/libpq/hba.c

@@ -1684,7 +1684,11 @@ parse_hba_line(TokenizedLine *tok_line, int elevel)
 	 */
 	if (parsedline->auth_method == uaCert)
 	{
-		parsedline->clientcert = clientCertCA;
+		/*
+		 * For auth method cert, client certificate validation is mandatory, and it implies
+		 * the level of verify-full.
+		 */
+		parsedline->clientcert = clientCertFull;
 	}
 
 	return parsedline;