Change image repository override information error log level

[wjun]

Bug description
We use pinniped with an oidc test user to create a context. During the login process, one information(in black) shown below which will confuse users:
anzu context create mgmte --endpoint=https://192.168.120.1 --insecure-skip
-tls-verify
[ok] successfully created a kubernetes context using the kubeconfig /root/.kube/config
[i] Checking for required plugins for context 'mgmte'...
[i] unable to get image repository override information for some of the plugins. Error: configmaps is forbidden: User "johndoe@example.com" cannot list resource "configmaps" in API group "" in the namespace "tanzu-cli-system"

Because there is no tanzu-cli-system on our k8s cluster, and there is no image repository override settings at all, so users cannot understand what this information means.

Expected behavior
The above error message should not show, or at least, the log level at

tanzu-cli/pkg/discovery/kubernetes.go

Line 100 in d3ef9a5

log.Infof("unable to get image repository override information for some of the plugins. Error: %v", err)

should not be the default one.

Steps to reproduce the bug / Relevant debug output

Output of tanzu version
All versions.
Environment where the bug was observed (cloud, OS, etc)