address code review comments

Author: vkarpov15

lib/query.js

@@ -2293,9 +2293,9 @@ Query.prototype.mongooseOptions = function(v) {
 
 Query.prototype._castConditions = function() {
   let sanitizeFilterOpt = undefined;
-  if (this.model != null && this.model.db.options?.sanitizeFilter != null) {
+  if (this.model?.db.options?.sanitizeFilter != null) {
     sanitizeFilterOpt = this.model.db.options.sanitizeFilter;
-  } else if (this.model != null && this.model.base.options?.sanitizeFilter != null) {
+  } else if (this.model?.base.options?.sanitizeFilter != null) {
     sanitizeFilterOpt = this.model.base.options.sanitizeFilter;
   } else {
     sanitizeFilterOpt = this._mongooseOptions.sanitizeFilter;