lava-v2-submit-jobs.py: remove default value for --submitted
lava-v2-submit-jobs.py: remove default value for --submitted

In the general case when jobs are submitted and do not need to be
tracked with a JSON file, the --submitted option is not used.  So
remove the default value as otherwise it is always defined.

Signed-off-by: Guillaume Tucker <e7e20b7c30f19d4ca6b81319ef81bf200369d137@collabora.com>

kernelci/lava-ci-staging,kernelci/lava-ci-staging,kernelci/lava-ci-staging