chore: Improved error handling and refactor

[simster7]

Closes #2165 by improving error handling to display the JSON response message when available, and not allow the submission of malformed yamls while displaying the reason they are malformed.

Also brings this functionality to CronWorkflow and WorkflowTemplate submission, which previously did not have it.

[alexec]

Rubber-stamp approval. I've not checked this out or tested it - so only merge if you have high confidence in the changes. Can you make sure that the workflow template one works? I'm pretty sure this is broken on master.

[codecov]

Codecov Report

Merging #2184 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #2184   +/-   ##
=======================================
  Coverage   11.71%   11.71%           
=======================================
  Files          51       51           
  Lines       26309    26309           
=======================================
  Hits         3081     3081           
  Misses      22833    22833           
  Partials      395      395

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[simster7]

Double checked everything works as intended.

Can you make sure that the workflow template one works? I'm pretty sure this is broken on master.

Yup, it was indeed broken. Fixed!