[release-v1.15] fix: correct clusterrole permissions (#4016)

[Cali0707]

This is a cherry pick of knative-extensions#4016 to make sure that post install jobs have the correct permissions in the clusterrole

[pierDipi]

/retest
/lgtm
/approve

[openshift-ci]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: Cali0707, pierDipi

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[openshift-ci]

New changes are detected. LGTM label has been removed.

[openshift-ci]

@Cali0707: The following tests failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
ci/prow/415-test-reconciler-keda-aws-415	4231275	link	true	/test 415-test-reconciler-keda-aws-415
ci/prow/415-test-reconciler-aws-415	4231275	link	true	/test 415-test-reconciler-aws-415
ci/prow/415-test-reconciler-encryption-auth-aws-415	4231275	link	true	/test 415-test-reconciler-encryption-auth-aws-415

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