Clean up deprecated team labels from devops label inference

There are still Deprecated team labels inference which adds some level of complexity in the #new_stage_and_group_labels_from_intelligent_inference in DevopsLabels triage helper.

• Manage [DEPRECATED] => devopsmanage
• Create [DEPRECATED] => devopscreate
• Plan [DEPRECATED] => devopsplan

Since the labels have description mentioning the replacement stage labels, we could remove these from the inference and simplify the logic in the method.

To deal with new issues being created that have these labels applied, we could set up a policy to nudge issue authors to relabel using the new set of labels (maybe using triage-serverless?). Once the issues have been relabeled, the usual hygiene policy will pick it up and apply the usual inference.

cc @gl-quality/eng-prod