Update volunteer exit email

When a volunteer commitment ends, volunteers are currently receiving an email with a link to an out-of-date survey. The email should be updated as follows:

Dear {{Name}},

Thank you for your volunteering with {{Project Name}}. Everyone at DemocracyLab deeply appreciates the time, skills, and passion you've dedicated to our mission of using technology for public good.

Now that your volunteer commitment has ended, we'd be grateful if you could complete this short [volunteer exit survey](https://docs.google.com/forms/d/e/1FAIpQLSfgBKitWyQcZh_61ScZuWXttl_n798mfRZTtgy3lNsqRiW0Zw/viewform?usp=sf_link) to help us continuously improve our platform and better support future volunteers. Your feedback is crucial in helping us understand the volunteer experience and quantify the impact of our collective work.

If you haven't already, we invite you to [join our newsletter](https://democracylab.us3.list-manage.com/subscribe/post?u=72af92d0a817dcbf3aa960ee0&id=d3b4c4d81c) to stay informed about our ongoing initiatives and opportunities.

Thank you again for your commitment and support,
The DemocracyLab team