Birthday calendar entries should show real birthday

Currently, birthday events list the current birthday date instead of the actual birth date.

added type::bug label

assigned to @hansegucker

added part::frontend label

created branch 914-birthday-calendar-entries-should-show-real-birthday to address this issue

mentioned in merge request !1344 (merged)

closed with merge request !1344 (merged)

mentioned in commit 70680b2f