fix: Error in derived materials in Three r170

They changed Material.type to a getter that queries the object's constructor

Author: lojjic

Diff for: packages/troika-three-utils/src/DerivedMaterial.js

@@ -66,7 +66,7 @@ let materialInstanceId = 1e10
  *        output value. Will be injected near the end of the `void main` function, but before any
  *        of ThreeJS's color postprocessing shader chunks (tonemapping, fog, etc.), and before the
  *        `fragmentMainOutro`.
- * @param {function({fragmentShader: string, vertexShader:string}): 
+ * @param {function({fragmentShader: string, vertexShader:string}):
  *        {fragmentShader: string, vertexShader:string}} options.customRewriter - A function
  *        for performing custom rewrites of the full shader code. Useful if you need to do something
  *        special that's not covered by the other builtin options. This function will be executed before
@@ -170,6 +170,11 @@ export function createDerivedMaterial(baseMaterial, options) {
     constructor: {value: DerivedMaterial},
     isDerivedMaterial: {value: true},
 
+    type: {
+      get: () => baseMaterial.type,
+      set: (value) => {baseMaterial.type = value}
+    },
+
     isDerivedFrom: {
       writable: true,
       configurable: true,