fix: remove attachment by id (#725)

Co-authored-by: Dominik Pschenitschni <mail@celement.de>
Reviewed-on: https://kolaente.dev/vikunja/frontend/pulls/725
Co-authored-by: dpschen <dpschen@noreply.kolaente.de>
Co-committed-by: dpschen <dpschen@noreply.kolaente.de>

src/helpers/find.ts

@@ -0,0 +1,3 @@
+export function findIndexById(array : [], id : string | number) {
+	return array.findIndex(({id: currentId}) => currentId === id)
+}