Electrum is still in Tails 6.12, just verified. The changelog just says they closed some issue related to donations.
https://gitlab.tails.boum.org/tails/tails/-/blob/master/debian/changelog
Closes issues:
- Revert Electrum donation incentive to out-of-donation-campaign status,
post-2024-fundraiser (tails/tails#20763)