Automatic merge from submit-queue (batch tested with PRs 61306, 60270, 62496, 62181, 62234). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

Handle partial group and resource responses consistently

GetAPIGroupResources tolerates partial discovery responses to provide as much information to the caller as possible.

Before skipping a particular error response, check whether the response was accompanied by partial group or resource data.

There's an existing TODO to propagate partial errors that I plan to address in a follow-up, but that had more ripples and I wanted to correct this first.

```release-note
NONE
```