fix(server): non-nullable IsOptional (#3939)

* custom `IsOptional`

* added link to source

* formatting

* Update server/src/domain/domain.util.ts

Co-authored-by: Jason Rasmussen <jrasm91@gmail.com>

* nullable birth date endpoint

* made `nullable` a property

* formatting

* removed unused dto

* updated decorator arg

* fixed album e2e tests

* add null tests for auth e2e

* add null test for person e2e

* fixed tests

* added null test for user e2e

* removed unusued import

* log key in test name

* chore: add note about mobile not being able to use the endpoint

---------

Co-authored-by: Jason Rasmussen <jrasm91@gmail.com>

server/immich-openapi-specs.json

@@ -6331,7 +6331,7 @@
       "PeopleUpdateItem": {
         "properties": {
           "birthDate": {
-            "description": "Person date of birth.",
+            "description": "Person date of birth.\nNote: the mobile app cannot currently set the birth date to null.",
             "format": "date",
             "nullable": true,
             "type": "string"
@@ -6390,7 +6390,7 @@
       "PersonUpdateDto": {
         "properties": {
           "birthDate": {
-            "description": "Person date of birth.",
+            "description": "Person date of birth.\nNote: the mobile app cannot currently set the birth date to null.",
             "format": "date",
             "nullable": true,
             "type": "string"