when postUrl returns a rejected promise, pass the whole response back instead of just 'Server failure'

[susanm74]

would make it easier for processing errors stored in the response.xyz (ex. response.body, response.json, response.json.error, response.json.file, etc) when it's desired to know more (or display more to the user) than just 'Server failure'

an idea that springs from issue 4347 / PR #276, but making a separate issue for this as the change itself and the testing burden would be nontrivial:

• postJSON and postFormData both make a call to postUrl
• postUrl is used directly by a few helpers and components:
  • contacts -> helpers -> closeTicket (although don't think this is actively used anywhere across TC, RP, FE repos)
  • Store
  • Modax
• postJSON is used directly by:
  • 8 components
• postFormData is used directly by:
  • 1 component

[susanm74]

@ericnewcomer @rowanseymour

[github-actions]

Without activity, this issue will be closed in 14 days.

[ericnewcomer]

Assigning this just so it doesn't auto-close