update gammajet herwig JOs

Description of bug

Fixed warning messages in JOs. The log file from JOs are quite large and the evgen job will use lots of disk space when running the job in node computer. That's why it should be fixed. The previous JOs haven't been used for any production.

Changes introduced

Herwig7Config.run(shower_var=False)

Tests

Have tested them locally. The extra warning messages are not there anymore.

Issues resolved

Sovled

Closes #