Update endpoint used by github action

[dequejenn]

BLOCKED: See epic for changes needed

Need to update the endpoint used by the github action to get the a11y threshold overage to use https://github.com/dequelabs/walnut/issues/7236. In addition, the github action should be updated to show those new fields:

In the PR comment:

1. Add in axe DevHub found X accessibility violations over your a11y threshold. where X is the number returned by the new endpoint <-- verify if this was done and just not yet released
2. Update the link to point to the URL returned by the new endpoint
   

In the Action display:
3. Update the number of violations over a11y threshold with the number returned from the new endpoint (line 33 in example screenshot below)
4. Update URL with URL returned by the new endpoint (like 34 in the example screenshot below)