Fix incorrect oldest sort in project list (#25806) (#25835)

Backport #25806 by @yp05327

sort type `oldest` should be `Asc`.
Added a test for this.

I see we have `SearchOrderBy` in db model, but we are using many
different ways to define the sort type.
~Maybe we can improve this later.~
↑ Improved in this PR

Co-authored-by: yp05327 <576951401@qq.com>

models/fixtures/project.yml

@@ -7,6 +7,8 @@
   creator_id: 2
   board_type: 1
   type: 2
+  created_unix: 1688973030
+  updated_unix: 1688973030
 
 -
   id: 2
@@ -17,6 +19,8 @@
   creator_id: 3
   board_type: 1
   type: 2
+  created_unix: 1688973010
+  updated_unix: 1688973010
 
 -
   id: 3
@@ -27,6 +31,8 @@
   creator_id: 5
   board_type: 1
   type: 2
+  created_unix: 1688973020
+  updated_unix: 1688973020
 
 -
   id: 4
@@ -37,3 +43,5 @@
   creator_id: 2
   board_type: 1
   type: 2
+  created_unix: 1688973000
+  updated_unix: 1688973000