Standardize the color of the Epic Link label across Jira's UI

Summary

Currently, if you have an Epic Link field in the view screen of a ticket, it will show a colored label with the text inside being white. However, in other screens like in the list view of a filter result or in boards, the text is black.

This lead to confusion sometimes, and the black text is also hard to see when the label color is dark (like brown or blue).

Suggestion

Standardize the white color texts in these colored labels across the whole application in Jira's UI.