Track user event users_updating_work_item_dates

What does this MR do and why?

Implements service ping to track users updating work item titles.

Context on how the metrics need to be implemented in #346046 (closed)

How to set up and validate locally

Currently the mutation to update a work item's dates is not merged. YOu can test the counters work manually in the rails console by doing something like:

Feature.enable :track_work_items_activity

Gitlab::UsageDataCounters::WorkItemActivityUniqueCounter.track_work_item_date_changed_action(author: User.first)

Gitlab::UsageDataCounters::HLLRedisCounter.unique_events(event_names: 'users_updating_work_item_dates', start_date: Date.current.beginning_of_week, end_date: Date.current.next_week)

As !93129 (merged) is merged, updating dates on a work item should increment the counter. THis can only be done via the GraphQL API. Example in !93129 (merged)

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #365399 (closed)