🛂(backend) match email if no existing user matches the sub

Some OIDC identity providers may provide a random value in the "sub"
field instead of an identifying ID. In this case, it may be a good
idea to fallback to matching the user on its email field.

CHANGELOG.md

@@ -16,6 +16,10 @@ and this project adheres to
 
 - ✨(backend) manage roles on domain admin view
 
+### Changed
+
+- 🛂(backend) match email if no existing user matches the sub
+
 ## [1.2.1] - 2024-10-03
 
 ### Fixed