fix(cache): since we add new secret from modelreg with cache, we need to lose the cache for istio-system ns

[zdtsw]

Description

it is causing problem in modelreg with reconcile in Operator pod
related to #1190

How Has This Been Tested?

Screenshot or short clip

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[zdtsw]

1 node(s) had untolerated taint {node-role.kubernetes.io/ci-builds-worker: ci-builds-worker}, 13 node(s) were unschedulable, 3 node(s) had untolerated taint {node-role.kubernetes.io/infra: }, 3 node(s) had untolerated taint {node-role.kubernetes.io/master: }, 6 node(s) didn't match Pod's node affinity/selector. no new claims to deallocate, preemption: 0/26 nodes are available: 26 Preemption is not helpful for scheduling..................

[zdtsw]

/retest

[zdtsw]

/retest

[VaishnaviHire]

/lgtm

[openshift-ci]

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