APlugin添加BPlugin通道一起注册方式

APlugin里加入
jtScanImgFilePlugin = JTScanImgFilePlugin()
jtScanImgFilePlugin.onAttachedToEngine(binding)
如下
override fun onAttachedToEngine(@NonNull binding: FlutterPlugin.FlutterPluginBinding) {
Log.e("scan", "onAttachedToEngine")
flutterBinding = binding
channel = MethodChannel(binding.binaryMessenger, "scan_plugin")
channel.setMethodCallHandler(this)
pdaEventChannel = EventChannel(binding.binaryMessenger, "scan_plugin_pda")
pdaEventChannel.setStreamHandler(this)
jtScanImgFilePlugin = JTScanImgFilePlugin()
jtScanImgFilePlugin.onAttachedToEngine(binding)
}