Fixing adding command problem

[josenavas]

Carolina and Stephanie found an issue in the qiita-rc system: if you tried to add a command to an artifact that has not been generated and the job generating it has been already submitted (i.e. no longer in construction), the system failed with a really weird error. Adding a command to those types of artifacts is not easy, there are a lot of assumptions perform through the code that rely on this behavior not happening, and removing all them is complex. For the time being, I've disabled the ability to add commands to those type of artifacts (you can still add commands if the workflow is in construction). Instead it shows a little information about that (there is not too much to show, but at least it doesn't fail and you see something on the screen). GIF with the resulting changes:

[codecov-io]

Codecov Report

Merging #2437 into dev will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##              dev    #2437   +/-   ##
=======================================
  Coverage   94.06%   94.06%           
=======================================
  Files         163      163           
  Lines       19347    19347           
=======================================
  Hits        18199    18199           
  Misses       1148     1148

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[josenavas]

@antgonza @ElDeveloper available for a review?