ClassCastException in FbxBindPose.fromElement()

[stephengold]

I'm testing current "master" branch with FBX assets downloaded from CGtrader, Mixamo, and Sketchfab.
Attempting to import a certain FBX file causes the following crash:

Jan 28, 2023 11:34:36 PM com.jme3.app.LegacyApplication handleError
SEVERE: Uncaught exception thrown in Thread[jME3 Main,5,main]
java.lang.ClassCastException: class java.lang.Double cannot be cast to class [D (java.lang.Double and [D are in module java.base of loader 'bootstrap')
	at com.jme3.scene.plugins.fbx.anim.FbxBindPose.fromElement(FbxBindPose.java:65)
	at com.jme3.scene.plugins.fbx.obj.FbxObjectFactory.createObject(FbxObjectFactory.java:192)
	at com.jme3.scene.plugins.fbx.FbxLoader.loadObjects(FbxLoader.java:195)
	at com.jme3.scene.plugins.fbx.FbxLoader.loadData(FbxLoader.java:161)
	at com.jme3.scene.plugins.fbx.FbxLoader.load(FbxLoader.java:110)
	at com.jme3.asset.DesktopAssetManager.loadLocatedAsset(DesktopAssetManager.java:272)
	at com.jme3.asset.DesktopAssetManager.loadAsset(DesktopAssetManager.java:388)
	at com.jme3.asset.DesktopAssetManager.loadModel(DesktopAssetManager.java:439)
	at com.jme3.asset.DesktopAssetManager.loadModel(DesktopAssetManager.java:444)
	at jme3test.helloworld.HelloJME3.loadModel(HelloJME3.java:88)
	at jme3test.helloworld.HelloJME3.simpleInitApp(HelloJME3.java:67)
	at com.jme3.app.SimpleApplication.initialize(SimpleApplication.java:240)
	at com.jme3.system.lwjgl.LwjglAbstractDisplay.initInThread(LwjglAbstractDisplay.java:139)
	at com.jme3.system.lwjgl.LwjglAbstractDisplay.run(LwjglAbstractDisplay.java:221)
	at java.base/java.lang.Thread.run(Thread.java:833)

The code in "FbxBindPose.java" assumes that the bind pose will come in the form of 16 properties of type Double, but the FBX format also allows it to be in the form of a single property of type Double[]. The FBX importer should handle both possibilities.

There's a similar issue in "FbxCluster.java", where the fromElement() method assumes weights and indexes will come in the form of array properties, but the FBX format also allows them each to be multiple properties. Let's solve those issues as well!