fix(sec): add tests for private issues on projects

- Add integration and unit tests to ensure that private issues on
projects are not shown in any way, shape or form when the doer has no
access to it.

models/fixtures/PrivateIssueProjects/project.yml

@@ -0,0 +1,23 @@
+-
+  id: 1001
+  title: Org project that contains private issues
+  owner_id: 3
+  repo_id: 0
+  is_closed: false
+  creator_id: 2
+  board_type: 1
+  type: 3
+  created_unix: 1738000000
+  updated_unix: 1738000000
+
+-
+  id: 1002
+  title: User project that contains private issues
+  owner_id: 2
+  repo_id: 0
+  is_closed: false
+  creator_id: 2
+  board_type: 1
+  type: 1
+  created_unix: 1738000000
+  updated_unix: 1738000000

models/fixtures/PrivateIssueProjects/project_board.yml

@@ -0,0 +1,17 @@
+-
+  id: 1001
+  project_id: 1001
+  title: Triage
+  creator_id: 2
+  default: true
+  created_unix: 1738000000
+  updated_unix: 1738000000
+
+-
+  id: 1002
+  project_id: 1002
+  title: Triage
+  creator_id: 2
+  default: true
+  created_unix: 1738000000
+  updated_unix: 1738000000

models/fixtures/PrivateIssueProjects/project_issue.yml

@@ -0,0 +1,11 @@
+-
+  id: 1001
+  issue_id: 6
+  project_id: 1001
+  project_board_id: 1001
+
+-
+  id: 1002
+  issue_id: 7
+  project_id: 1002
+  project_board_id: 1002