Automatic additional properties mapping for Snowplow tracking

What does this MR do and why?

This MR adds functionality to automatically map standard Snowplow properties for Internal Events tracking.

For a given event described like

additional_properties:
  error_code:
  execution_time:

and tracking call

  Gitlab::InternalEvents.track_event(
    'user_created_project',
    additional_properties: { 
      error_code: 'stackoverflow',
      execution_time: '10s'
    },
  )

Internal Events will automatically map error_code -> label and execution_time -> property for Snowplow tracking while keeping the original properties intact.

Implemented with internal_events_automatic_property_mapping FF

Rollout issue #565697 (closed)

References

Screenshots or screen recordings

Before	After

How to set up and validate locally

MR acceptance checklist

Evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Related to #444307 (closed)