added dispose() method to Reflector and Refractor classes (#22932)

* added dispose() method to Reflector and Refractor classes

* dispose internal material in Reflector and Refractor

examples/jsm/objects/Reflector.js

@@ -193,6 +193,13 @@ class Reflector extends Mesh {
 
 		};
 
+		this.dispose = function () {
+
+			renderTarget.dispose();
+			scope.material.dispose();
+
+		};
+
 	}
 
 }

examples/jsm/objects/Refractor.js

@@ -262,6 +262,13 @@ class Refractor extends Mesh {
 
 		};
 
+		this.dispose = function () {
+
+			renderTarget.dispose();
+			scope.material.dispose();
+
+		};
+
 	}
 
 }