Fix classcast exception using NcFormat 4 in D-Flow FM

[erikpelgrim]

java.lang.ClassCastException: class [F cannot be cast to class [D ([F and [D are in module java.base of loader 'bootstrap')
at ucar.nc2.jni.netcdf.Nc4Iosp.writeData(Nc4Iosp.java:2242)
at ucar.nc2.jni.netcdf.Nc4Iosp.writeData(Nc4Iosp.java:2203)
at ucar.nc2.NetcdfFileWriter.write(NetcdfFileWriter.java:800)
at ucar.nc2.NetcdfFileWriter.write(NetcdfFileWriter.java:784)
at org.openda.model_dflowfm.DFlowFMRestartFileWrapper.finish(DFlowFMRestartFileWrapper.java:358)
at org.openda.blackbox.wrapper.BBModelInstance.flushAndClearDataObjects(BBModelInstance.java:690)
at org.openda.blackbox.wrapper.BBModelInstance.compute(BBModelInstance.java:246)
at org.openda.blackbox.wrapper.BBStochModelInstance.compute(BBStochModelInstance.java:356)