Migrate away from unmaintained golang/mock

[dttung2905]

Proposal

While working on #5391 and go generics, I realise that gomock is no longer maintained as per official doc. It does not support mocking generics too (discussion link, gh issue)

Update, June 2023: This repo and tool are no longer maintained. Please see [go.uber.org/mock](https://github.com/uber/mock) for a maintained fork instead

We should migrate away from gomock to something else, probably go.uber.org/mock. I can take a look at this issue this week if I have time

Use-Case

No response

Is this a feature you are interested in implementing yourself?

Yes

Anything else?

No response

[rahulii]

/assign