Search for keywords in the comments of epics

Problem to solve

Customer is requesting that epic searches allow for keywords of user comments.

Further details

As described in the Epics docs only the following criteria is currently supported in search:

• Title or description
• Author name / username
• Labels

Proposal

Index keywords of comments and make searchable.

What does success look like, and how can we measure that?

(If no way to measure success, link to an issue that will implement a way to measure this)

Links / references

Edit: Adding correct ticket link: https://gitlab.zendesk.com/agent/tickets/109425