casting issues for nightlies

[ankona]

Fix two defects created in the typehinting PRs:

1. The job-id was cast to an integer and should have been a string
2. A test for task_id having a null-or-zero value was added to incorrectly guard against adding steps without task_id from being added to history

[MattToast]

lgtm

[codecov]

Codecov Report

Merging #310 (ce7632a) into develop (e6e563a) will not change coverage.
The diff coverage is 100.00%.

Additional details and impacted files

@@           Coverage Diff            @@
##           develop     #310   +/-   ##
========================================
  Coverage    87.54%   87.54%           
========================================
  Files           59       59           
  Lines         3461     3461           
========================================
  Hits          3030     3030           
  Misses         431      431           

Impacted Files	Coverage Δ
smartsim/_core/launcher/launcher.py	100.00% <ø> (ø)
smartsim/_core/control/job.py	93.42% <100.00%> (ø)
smartsim/_core/control/jobmanager.py	94.30% <100.00%> (ø)
smartsim/_core/launcher/stepMapping.py	74.41% <100.00%> (ø)

[MattToast]

One small question, but otherwise lgtm!