[release-v1.15] Remove conversion webhook config in EventPolicy CRD

[creydr]

As we don't have multiple EventPolicy versions yet, we don't need the conversion webhook configuration in the EventPolicy CRD.

Cherry-pick of https://github.com/knative/eventing/pull/8379/files

/cherry-pick release-v1.16

[openshift-ci]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: creydr

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [creydr]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[pierDipi]

please re-run make generate-release

[openshift-cherrypick-robot]

@creydr: new pull request created: #984

In response to this:

As we don't have multiple EventPolicy versions yet, we don't need the conversion webhook configuration in the EventPolicy CRD.

Cherry-pick of https://github.com/knative/eventing/pull/8379/files

/cherry-pick release-v1.16

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.