[tempo-distributed] Removing Job Selector Config

[jordan-simonovski]

Many apologies! This is on me for not properly verifying the Jobs prior to raising my previous PR.

Templating with a config like the following

  selector:
  template:
    metadata:
      labels:
        app.kubernetes.io/component: tokengen-job-2

will throw the error:

selector` does not match template `labels`, spec.selector: Invalid value: "null": field is immutable

On the other hand, adding in the selector labels will also fail as Kubernetes will throw the following error:

 `selector` not auto-generated

I've given this a much more rigorous test, and apologies for my previous bad change 🙏

The Selector should not be manually specified unless otherwise configured in spec. Removing the selector altogether ensures the job configuration is valid, while also allowing for templating without null values causing errors.

[kvrhdn]

This is a revert of #3111 right?

[zalegrala]

The chart version will need a bump and the docs need an update.

[jordan-simonovski]

This is a revert of #3111 right?

It's not so much a revert as much as it is just removing the whole selector key from the config.
We could revert and keep selector: but this still seems to trigger the issue when templating which throws Invalid value: "null"

I have verified that upon removing this from the template that Kube will still add the selector config with the auto-generated selector value.

[zalegrala]

Thanks for coming back. I've rebased bumped the chart version for the PR.