must-gather: numaresources: Avoid error messages when NRO is not installed

[jlojosnegros]

must-gather is trying to get NRO related information (CRDs, and namespaced artifacts) no matter what and so, when NRO is not installed in the cluster some nasty error messages appear because those elements are not found.

These are not errors but to avoid missleading the users it is better to avoid them by not gathering the NRO information if we cannot detect the NRO namespace. A small message appears in console in this case.

[jlojosnegros]

/cc @shajmakh /hold till fully tested

[coveralls]

Pull Request Test Coverage Report for Build 2609

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 60.463%

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Totals
Change from base Build 2598:	0.0%
Covered Lines:	1644
Relevant Lines:	2719

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💛 - Coveralls

[shajmakh]

Thanks! /lgtm

[jlojosnegros]

/unhold

[jlojosnegros]

I think the two failing ci lanes need to be overridden

[ffromani]

/override ci/prow/e2e-gcp

[openshift-ci[bot]]

@fromanirh: Overrode contexts on behalf of fromanirh: ci/prow/e2e-gcp

In response to [this](https://github.com/openshift-kni/performance-addon-operators/pull/939#issuecomment-1238150553): >/override ci/prow/e2e-gcp > Instructions for interacting with me using PR comments are available [here](https://git.k8s.io/community/contributors/guide/pull-requests.md). If you have questions or suggestions related to my behavior, please file an issue against the [kubernetes/test-infra](https://github.com/kubernetes/test-infra/issues/new?title=Prow%20issue:) repository.

[ffromani]

/override ci/prow/e2e-gcp-operator-upgrade

[ffromani]

/approve

[openshift-ci[bot]]

@fromanirh: Overrode contexts on behalf of fromanirh: ci/prow/e2e-gcp-operator-upgrade

In response to [this](https://github.com/openshift-kni/performance-addon-operators/pull/939#issuecomment-1238150757): >/override ci/prow/e2e-gcp-operator-upgrade Instructions for interacting with me using PR comments are available [here](https://git.k8s.io/community/contributors/guide/pull-requests.md). If you have questions or suggestions related to my behavior, please file an issue against the [kubernetes/test-infra](https://github.com/kubernetes/test-infra/issues/new?title=Prow%20issue:) repository.

[openshift-ci[bot]]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: fromanirh, jlojosnegros

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