[occm]: remove k8s annotations after LB is deleted

[chnyda]

What this PR does / why we need it:
If a service was previously of type LoadBalancer, then was switched to another type (for instance NodePort) and the service is switched again to LoadBalancer : the LoadBalancer fails to be created because the LoadBalancer cannot be found (based on the ID from the annotations).

Which issue this PR fixes(if applicable):
fixes #2751

Special notes for reviewers:

Release note:

NONE

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