Add front and back guard for undefined

[jmthomas]

This was observed in the wild in a bad deployment where a script hung and thus didn't create a log. The request for the log resulted in a bad URL path. Add a check for the log in the frontend and a sanity check in the backend.

[codecov]

Codecov Report

❌ Patch coverage is 33.33333% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 79.34%. Comparing base (56a2a5f) to head (c7f9ed1).

Files with missing lines	Patch %	Lines
...-cmd-tlm-api/app/controllers/storage_controller.rb	33.33%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3556      +/-   ##
==========================================
+ Coverage   79.29%   79.34%   +0.04%     
==========================================
  Files         691      691              
  Lines       57724    57730       +6     
  Branches      728      728              
==========================================
+ Hits        45773    45803      +30     
+ Misses      11873    11849      -24     
  Partials       78       78              

Flag	Coverage Δ
python	80.31% <ø> (ø)
ruby-api	81.43% <33.33%> (+0.54%)	⬆️
ruby-backend	83.21% <ø> (ø)

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[sonarqubecloud]

Quality Gate failed

Failed conditions
4.3% Duplication on New Code (required ≤ 3%)

See analysis details on SonarQube Cloud

[jmthomas]

Does the frontend guard also cover the interval between requesting a log and the backend returning that no log exists, or only an initially undefined value? A regression test for a script record that exists but never acquires a log identifier could verify that neither navigation nor polling constructs a path containing undefined.

I think we're fully covered on that path but I did find another path in RunningScripts where we download the log.