doc(UMDExample): Update itk.js to 12.4.0
doc(UMDExample): Update itk.js to 12.4.0

thewtex/ITKBridgeJavaScript,InsightSoftwareConsortium/ITKBridgeJavaScript,InsightSoftwareConsortium/ITKBridgeJavaScript,InsightSoftwareConsortium/ITKBridgeJavaScript,thewtex/ITKBridgeJavaScript,thewtex/ITKBridgeJavaScript