InstancedMesh: Remove .type.

src/objects/InstancedMesh.d.ts

@@ -16,7 +16,6 @@ export class InstancedMesh extends Mesh {
 	count: number;
 	instanceMatrix: BufferAttribute;
 	isInstancedMesh: true;
-	type: 'InstancedMesh';
 
 	setMatrixAt( index: number, matrix: Matrix4 ): void;
 

src/objects/InstancedMesh.js

@@ -13,8 +13,6 @@ function InstancedMesh( geometry, material, count ) {
 
 	this.count = count;
 
-	this.type = 'InstancedMesh';
-
 }
 
 InstancedMesh.prototype = Object.assign( Object.create( Mesh.prototype ), {