apisix dashboard Grafana Access errors

[xiaolei000129]

I use the apisix-docker\example\docker-compose.yml deploy apisix
apisix-docker\example\dashboard_conf\conf.yaml

Access http://127.0.0.1:9000/dashboard Grafana Access errors

[tokers]

cc @bzp2010

[Chever-John]

csp rule problem.
you can refer to this PR.
@xiaolei000129