Don't disable grafana alerting

I lost a bunch of time today trying to figure out why
this default feature was not enabled.

Ref #7166

Author: yuvipanda

helm-charts/support/values.yaml

@@ -326,10 +326,6 @@ grafana:
       # Because our grafana is behind an nginx ingress, this should match the
       # read timeout set above under `ingress.annotations`.
       timeout: 120
-    unified_alerting:
-      # Disable alerting for now as its not something our community users can
-      # setup. See https://github.com/2i2c-org/infrastructure/issues/4919.
-      enabled: false
     server:
       root_url: ""
       enable_gzip: true