ci(.github): add retry to download artifacts to work around the RequestTimeout issue of downloading artifacts

[jijiechen]

The download-artifact action plugin was updated to v4 recently and we are seeing request timeouts after that updating.
This is a known issue at GitHub Actions server side and it's tracked at actions/download-artifact#249

I'm adding some retries to work around this issue for the moment. This work around does not break the main run process, we can see successful artifact downloading from the following run:

https://github.com/jijiechen/kuma/actions/runs/7394542119/job/20117851713

(The run failed eventually because of flaky e2e tests, but we can stil know the PR here will not break the CI process)

Checklist prior to review

• Link to relevant issue as well as docs and UI issues
  • https://github.com/kumahq/kuma/actions/runs/7291088227/job/19869652348#step:9:21
• This will not break child repos: it doesn't hardcode values (.e.g "kumahq" as a image registry) and it will work on Windows, system specific functions like syscall.Mkfifo have equivalent implementation on the other OS
  • Confirmed
• Tests (Unit test, E2E tests, manual test on universal and k8s)
  • Manual tested
  • Don't forget ci/ labels to run additional/fewer tests
    • No need to add
• Do you need to update UPGRADE.md?
  • No
• Does it need to be backported according to the backporting policy? (this GH action will add "backport" label based on these file globs, if you want to prevent it from adding the "backport" label use no-backport-autolabel label)
  • No