Bugfix - Persist forced feature values through refresh

[bttf]

This PR fixes an issue in our DevTools extension where forced values do not persist through refreshes of the inspected window.

Reports from customers:

• https://growthbookusers.slack.com/archives/C01T6Q1SVFV/p1706801125408999
• https://share.vidyard.com/watch/LjrLjdHJMQyCx1gsFaaZ8X

Screencap: