404 Validation error comments should specify the failing URL

[XLTechie]

Actual:

If the submission validation scripts encounter a failing URL, the error left as a comment on the issue does not specify the URL.
The submitter may not therefore know which URL is failing to resolve, and may waste time trying to debug URLs that aren't the problem.

Example:

Validation Errors for addons/ADDON_NAME/VERSION.json:
• Fatal error, unable to continue: HTTP Error 404: Not Found

Expected:

The failing URL is given in the comment.

Example:

Validation Errors for addons/ADDON_NAME/VERSION.json:
• Fatal error, unable to continue: HTTP Error 404: Not Found
URL: https://something.tld/someUser/ADDON_NAME-VERSION.nvda-addon

Additional Context:

First noticed in #3244.

[XLTechie]

Actually, @seanbudd, in looking at sendJsonFile.yml: In step "Download add-on", it causes an error of "Error with downloading add-on from download URL", if curl meets an error in that circumstance. So, the situation in #3244 already shouldn't have had that error text, if it was a problem with the add-on URL as you indicated.