Migrate epic events to snowplow vol. 4 - epic issues events

What does this MR do and why?

Related to #366827 (closed)

Migrate some of the redis_hll_counters.epics_usage.epics_usage_total_unique_counts_monthly event's sub-events to Snowplow.

Screenshots or screen recordings

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How to set up and validate locally

1. Enable snowplow micro
2. Trigger any of the events migrated here:

• add an issue to an epic
• remove an issue from an epic
• move an epic's issue into a different project
• change epic's parent or children epics
• close an epic
• reopen an epic
• promote an issue to epic

3. Check if a new event with perform_epics_action action and se_property attribute describing the performed action has been registered at localhost:9090/micro/good

MR acceptance checklist

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