Reading GRIB2: jas_get_ctx_internal: Assertion `ctx' failed

NCL 6.6.2 is not able to read certain GRIB2 files from ECMWF.  Multiple platforms.  GRIB2 reader needs to be updated.  Original NCL user report:
https://mailman.ucar.edu/pipermail/ncl-talk/2025-November/019505.html

Related upstream issue:
https://github.com/jasper-software/jasper/issues/373