Fix positional note specs

These specs needed a persisted project and merge request

spec/models/diff_note_spec.rb

@@ -35,7 +35,9 @@ RSpec.describe DiffNote do
   subject { create(:diff_note_on_merge_request, project: project, position: position, noteable: merge_request) }
 
   describe 'validations' do
-    it_behaves_like 'a valid diff positionable note', :diff_note_on_commit
+    it_behaves_like 'a valid diff positionable note' do
+      subject { build(:diff_note_on_commit, project: project, commit_id: commit_id, position: position) }
+    end
   end
 
   describe "#position=" do

spec/models/draft_note_spec.rb

@@ -5,11 +5,13 @@ require 'spec_helper'
 RSpec.describe DraftNote do
   include RepoHelpers
 
-  let(:project)       { create(:project, :repository) }
-  let(:merge_request) { create(:merge_request_with_diffs, target_project: project, source_project: project) }
+  let_it_be(:project)       { create(:project, :repository) }
+  let_it_be(:merge_request) { create(:merge_request_with_diffs, target_project: project, source_project: project) }
 
   describe 'validations' do
-    it_behaves_like 'a valid diff positionable note', :draft_note
+    it_behaves_like 'a valid diff positionable note' do
+      subject { build(:draft_note, merge_request: merge_request, commit_id: commit_id, position: position) }
+    end
   end
 
   describe 'delegations' do

spec/support/shared_examples/models/diff_positionable_note_shared_examples.rb

@@ -18,8 +18,6 @@ RSpec.shared_examples 'a valid diff positionable note' do |factory_on_commit|
       )
     end
 
-    subject { build(factory_on_commit, commit_id: commit_id, position: position) }
-
     context 'position diff refs matches commit diff refs' do
       it 'is valid' do
         expect(subject).to be_valid