Automatic merge from submit-queue (batch tested with PRs 43777, 44121)

Add patchMergeKey and patchStrategy  support to OpenAPI

Support generating Open API extensions for strategic merge patch tags in go struct tags
Support `patchStrategy` and `patchMergeKey`.
Also support checking if the Open API extension and struct tags match.

```release-note
Support generating Open API extensions for strategic merge patch tags in go struct tags
```

cc: @pwittrock @ymqytw 

(Description mostly copied from #43833)