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/src/domain/user/dto/user-count.dto.ts

@@ -1,9 +1,10 @@
+import { Optional } from '../../domain.util';
 import { Transform } from 'class-transformer';
-import { IsBoolean, IsOptional } from 'class-validator';
+import { IsBoolean } from 'class-validator';
 
 export class UserCountDto {
   @IsBoolean()
-  @IsOptional()
+  @Optional()
   @Transform(({ value }) => value === 'true')
   /**
    * When true, return the number of admins accounts