[grafana] Fix for cve-2021-25742 is incorrect - not fixable here

[afirth]

#1481 introduced allow-snippet-annotations: false all configmaps in the chart. However, this configuration is only a valid input to ingress-nginx, via it's configmap (not modified or created by any chart in this repo). It looks like this linter is incorrectly flagging it - maybe that's why the change was made.

The correct fix is documented in the description of kubernetes/kubernetes#126811 under Mitigation and is outside the scope of this repository.

Suggest fix: kubernetes/ingress-nginx#1543 (reverts kubernetes/ingress-nginx#1481)

[afirth]

attention @zanac1986 @zanhsieh