attica and knewstuff backport requests

[Nate Graham]

Hello distros!

We made some changes to KNewStuff/OSC server utilization to alleviate a 
recent unexpected flood of traffic. I'd like to request that these 
commits be backported:
- 
https://invent.kde.org/frameworks/attica/-/commit/04bd6dcd39895ce3637145e719c3c427bc7f1ca1
- 
https://invent.kde.org/frameworks/knewstuff/-/commit/f687c5abd0c5e9bd5a6688b6d9d50f2536b7d33d

These fixes will be in Frameworks 5.87, but it's quite important to get 
them to users of older frameworks too, to reduce the server utilization 
ASAP and help us identify the problematic senders of all this traffic.

Nate