ISOBinaryFieldPackager doesn't check max length when packing variable length fields

[hello-koval]

https://github.com/jpos/jPOS/blob/d1f202f65353b4ea52f8347e32424dbdc8c35ca6/jpos/src/main/java/org/jpos/iso/ISOBinaryFieldPackager.java#L104

It looks like there should be a check for variable length fields too. E.g., if I created new IFB_LLLHBINARY( 9999, "xxx") packager, I would expect an exception when packing 10000 bytes.