Harness attempts to submit job script even when job template does not exist

[hagertnl]

Testing this on a branch with console log levels manually increased, I get the following in stdout:

Path to Source: /autofs/nccs-svm1_proj/stf016/hagertnl/harness/unit_tests/harness_unit_tests/Source
Path to Build Dir: /lustre/orion/proj-shared/stf016/hagertnl/harness_sspace/crusher/05.12.23-11.07/harness_unit_tests/test_no_slurm_template/1683904267.9790764/build_directory
WARNING: Ignoring invalid built-in parameter key launch_id
In function make_batch_script_for_linux: Error opening bath template file 'slurm.template.x' for reading.Handling error: [Errno 2] No such file or directory: 'slurm.template.x'

build exit value = 0
submit exit value = 0
Skipped 0, launched 1.

The submit exit value = 0 line should not be there. The job never reached the submit, or at least, it shouldn't have.
This builds on issue #37 .