Add priorityClassName to all daemonsets

[ceastman-r7]

I tried enabling profiling but some pods are pending because they don't have a priorityClassName.

I am thinking something like:

alloy-profiles:
  priorityClassName: highPriority

[petewall]

I'm not sure if I want to pre-set a priorityClassName because highPriority might not exist on the particular cluster.

It is already set-able in the Alloy chart: https://github.com/grafana/alloy/blob/main/operations/helm/charts/alloy/values.yaml#L217

Which means that anyone can set it by adding:

alloy-profiles:
  controller:
    priorityClassName: highPriority

I can add a note to the troubleshooting section that shows how to set this, if you think that'd be sufficient.