Don't require access check for fixed_in_version

handle_bug_threshold is documented as the threshold at which someone can
be assigned to a bug. Therefore we shouldn't be checking this threshold
when changing the fixed_in_version field - update_bug_threshold is
enough (we use it for every other field).

Fixes #10647

core/bug_api.php

@@ -163,14 +163,6 @@ public function __set($name, $value) {
 			case 'category_id':
 				$value = (int)$value;
 				break;
-
-			case 'fixed_in_version':
-				if ( !$this->loading ) {
-					if ( !access_has_project_level( config_get( 'handle_bug_threshold' ) ) ) {
-						trigger_error( ERROR_ACCESS_DENIED, ERROR );
-					}
-				}
-				break;
 			case 'target_version':
 				if ( !$this->loading ) {
 					# Only set target_version if user has access to do so