Replaced the duplicated `extractDTagValue` method in `RevertModal.js` with the standard `getDTagValueFromTags` utility from `js/nostr/nip71.js`.
Verified by adding a new unit test suite `tests/nostr/nip71-d-tag.test.mjs` ensuring the utility covers all edge cases.
This improves code health by reducing duplication and centralizing NIP-71 logic.
Co-authored-by: PR0M3TH3AN <[email protected]>