Add Gitlab Internal Events to Frontend to unify RedisHLL/Snowplow

What does this MR do and why?

#410518 (closed)

Created trackInternalEvent on the frontend, which, with a single call, tracks an Event via Snowplow but also increments an according RedisHLL counter.

This change is similar to !118928 (diffs) for backend.

For example, I have updated devops_adoption_app.vue file where we are calling two methods to track. With this unified API, we can track with only one API.

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

1. In GDK go to http://127.0.0.1:3000/admin/dev_ops_reports
2. Click on the dev tab, there will be two API calls of snowplow and /increment_unique_users are being called
3. Before this change also, those two were called, difference is now we are calling this.trackInternalEvent instead of two seperate functions inside devops_adoption_app.vue component.

MR acceptance checklist

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