Backport v16: Replace deprecated github.com/golang/mock with go.uber.org/mock #13512 #13601

[shlomi-noach]

Description

Manual backport of #13512 into release-16.0

github.com/golang/mock is deprecated, and the repository has been archived. The recommended replacement is go.uber.org/mock.

[vitess-bot]

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[shlomi-noach]

In v16 we seem to have a dependency on github.com/golang/mock/mockgen (tools/tools.go) or which there's no equivalent in go.uber.org/mock.
Closing this PR for now.