CI: Compat checks: Make fetching the reference API more robust

[RedworkDE]

The GDExtension compat checks have recently been occasionally warning about all entries in the expected file, presumably because the reference API file has failed to download.

Thus:

• Switch wget from quiet to non-verbose mode so that in the future any such failures leave a trail in the log.
• Enable wget's retrying for 503 responses (which presumably was the response from the cache server when the failures occurred)
• Fail the CI step when the download still fails, as in that case the check cannot be executed.

[YuriSizov]

I noticed it as well, thanks for a quick fix! Do we want to limit the number of retries? I seems to default to 20 IIUC, which is probably excessive. I'd say 3 should be enough.

[RedworkDE]

I noticed that retry limit but I thought that the defaults are probably fine and left it at them.
I supposed if we ever run into a case where it gets stuck in the download we can still reduce the retry limit.

[YuriSizov]

Well if it fails to download, 20 retries would just waste CI time. It's either a fluke, and a couple retries would fix it, or it's a problem and 20 retries won't change anything.

[RedworkDE]

I reduced the maximum retries and timeout.

[YuriSizov]

Thanks!