ci:tests: dedup the fuzzer

[acpana]

This is really cool! I'm just catching up on it. 

I was looking to add something similar to this for these:

https://github.com/GoogleCloudPlatform/k8s-config-connector/blob/790c54b1bae78e405615273abbd7e54376180a7d/dev/tasks/find-missing-fields#L23-L46

Which gets ran in:

https://github.com/GoogleCloudPlatform/k8s-config-connector/blob/790c54b1bae78e405615273abbd7e54376180a7d/.github/workflows/fuzz.yaml#L31-L47

It seems we might've raced a bit here. Happy to clean up the old way of doing things and migrate away to the new one!

_Originally posted by @acpana in https://github.com/GoogleCloudPlatform/k8s-config-connector/pull/2995#discussion_r1829905636_