Fixes#288
### Motivation
When specifying multiple roles in `.Values.auth.superUsers` the values are converted to a comma-separated list by piping the dict through `values` and `join` in helm templating, `values` however doesn't guarantee that the order of elements will be the same every time. Therefor it recommends also passing it through `sortAlpha` to sort the list alphabetically.
This is a problematic when `.Values.broker.restartPodsOnConfigMapChange` is enabled because the checksum of the configmap changes every time the list's order is changed, resulting in the statefulsets rolling out a new version of the pods.
### Modifications
Pass list through `sortAlpha`.
### Verifying this change
- [x] Make sure that the change passes the CI checks.
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