Fix #9189 - API Allow only specific Colums to be updated on Issue (#9539)

* dont insert "-1" in any case to issue.poster_id

* Make sure API cant override importand fields

* code format

* fix lint

* WIP test

* add missing poster_id

* fix test

* user.IsGhost handle nil

* CI.restart()

* make sure no -1 is realy added

* CI.restart()

* @lunny suggestion remove some not allowed fields

* seperate issue.LoadMilestone

* load milestone and return it on IssueEdit via API

* extend Test for TestAPIEditIssue

* fix fixtures

* declare allowedColumnsUpdateIssueByAPI only once

* Update Year

* no var just write id drecty into func cal

Co-authored-by: Lauris BH <lauris@nix.lv>

models/fixtures/milestone.yml

@@ -21,3 +21,11 @@
   content: content3
   is_closed: true
   num_issues: 0
+
+-
+  id: 4
+  repo_id: 42
+  name: milestone of repo42
+  content: content random
+  is_closed: false
+  num_issues: 0