[JIRAALIGN-2030] API 2.0: Need to add 'Funding Stage' to the Epic API

Issue Summary

API 2.0: Need to add 'Funding Stage' to the Epic API

Steps to Reproduce

1. Run GET Epic in API 2.0 for an epic that has a Funding Stage defined.
2. Check if the Funding Stage appears in the response.

Expected Results

Funding Stage should be supported in all methods.

Actual Results

Funding Stage doesn't appear in the response

Workaround

Currently there is no known workaround for this behavior. A workaround will be added here when available