Change issue text on third party failure (#496)

It can be confusing to click on an old issue, click the first red thing
you see and you're seeing some new failure, not the old one

This has tripped me up before and it looks like it briefly tripped up
Daraan yesterday

.github/workflows/third_party.yml

@@ -412,5 +412,5 @@ jobs:
               owner: "python",
               repo: "typing_extensions",
               title: `Third-party tests failed on ${new Date().toDateString()}`,
-              body: "Runs listed here: https://github.com/python/typing_extensions/actions/workflows/third_party.yml",
+              body: "Full history of runs listed here: https://github.com/python/typing_extensions/actions/workflows/third_party.yml",
             })