Update NetworkPolicy guidelines to reflect the correct namespace

[sztyup]

Fix the misleading statement about namespaces for the HTTP01 solver pods.

The solver pods are always created in the namespace of the Challange resource (which is in the namespace of the Ingress/Certificate)
This can be verified in the code: https://github.com/cert-manager/cert-manager/blob/master/pkg/issuer/acme/http/pod.go#L180

[cert-manager-prow]

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[Copilot]

Pull Request Overview

This PR corrects inaccurate documentation about where cert-manager creates acmesolver resources for ACME HTTP01 challenges. The documentation previously incorrectly stated that these resources are created in the cert-manager namespace when using a ClusterIssuer.

• Updated the description of where acmesolver resources are created during ACME HTTP01 challenges

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[Copilot]

[nitpick] While technically correct, 'in the namespace of the Challenge resource' is somewhat circular. Consider clarifying this to 'in the same namespace as the Certificate resource' since Challenge resources are created in the same namespace as their parent Certificate, which is more immediately useful information for users planning network policies.

Suggested change

	in the namespace of the Challenge resource.
	in the same namespace as the Certificate resource.

[sztyup]

I do not think this change would make it more clear, because the Certificate resource is not necessarily created by the user (Ingress, Gateway, etc.) or it may not even be created, if directly using CertificateRequest. I think the Challenge is the most appropriate for this documentation.