ILS-233 Add additional check to prevent adding terminating namespace to OperatorGroup

[alicenoknow]

Follow-up to: #945

Currently terminating namespace can be added by our operandrequests-discovery feature to the OpertorGroup. In such case operator cannot create bindings in that namespace and crashes.

[ljeda]

just for the context, this is not really a real scenario as the normal scenario would be:

• Namespace gets created,
• OperandRequest gets created,
• LS creates bindings,
• Namespace gets removed (and it stucks in Terminating state for a while).

In such scenario I assume LS will not crash (at least immediately) as the bindings were already created.

Anyway, this is not a regression, so this does not need to be included in SC2 4.6.8.

[alicenoknow]

Test scenarios

1. OperandRequest from terminating namespace -> LS should not add namespace to OperatorGroup
2. Terminating namespace in OperatorGroup -> LS should remove namespace from OperatorGroup (job runs every 1h)
3. OperandRequest from non-existing namespace -> LS should not add namespace to OperatorGroup
4. Non-existing namespace already in OperatorGroup -> LS should remove namespace from OperatorGroup (job runs every 1h)

LS operator image:

docker-na-public.artifactory.swg-devops.com/hyc-cloud-private-scratch-docker-local/ibmcom/ibm-licensing-operator:ILS-233-operandrequest-terminating

[kflorianski-ibm]

Shouldn't this just be like so now?

if err != nil {
	return false, err
}

[ibm-ci-bot]

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