Award emojis to work item notes

What does this MR do and why?

Enable feature flag for work item note award emojis.

From slack discussion

How to set up and validate locally

1. Disable work_items_mvc_2 feature flag
2. Load a work item (and OKR or create a Task on an issue)

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.