[GBAK, Restore] The skip of att_functionarg_field_precision is corrected (#7852)

This commit fixes the issue #7851.

Author: dmitry-lipetsk

src/burp/restore.epp

@@ -4753,7 +4753,10 @@ void get_function_arg(BurpGlobals* tdgbl, bool skip_arguments)
 				break;
 
 			case att_functionarg_field_precision:
-				get_int32(tdgbl);
+				if (tdgbl->RESTORE_format >= 6)
+					get_int32(tdgbl);
+				else
+					bad_attribute(scan_next_attr, attribute, 90);
 				break;
 
 			case att_functionarg_package_name: