fix absend response by adding small delay in zookeeper check scripts

[langemar]

Running the pipes will close nc after sending commands immediately, which might not let zk time to respond to the request. Given a small delay fix false positives.

Not waiting for the response will (in case of zkOk) result in a lot of failing liveness probes and will restart the pod unnecessarily.

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[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: langemar
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We suggest the following additional approver: bprashanth

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[langemar]

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