Fix Gitlab/DelegatePredicateMethods offenses

Changelog: other

.rubocop_todo/gitlab/delegate_predicate_methods.yml

@@ -4,7 +4,6 @@ Gitlab/DelegatePredicateMethods:
   - app/models/clusters/cluster.rb
   - app/models/clusters/platforms/kubernetes.rb
   - app/models/concerns/ci/metadatable.rb
-  - app/models/concerns/diff_positionable_note.rb
   - app/models/concerns/integrations/base_data_fields.rb
   - app/models/concerns/resolvable_discussion.rb
   - app/models/project.rb

app/models/concerns/diff_positionable_note.rb

@@ -3,7 +3,6 @@ module DiffPositionableNote
   extend ActiveSupport::Concern
 
   included do
-    delegate :on_text?, :on_image?, to: :position, allow_nil: true
     before_validation :set_original_position, on: :create
     before_validation :update_position, on: :create, if: :on_text?, unless: :importing?
 
@@ -34,6 +33,14 @@ module DiffPositionableNote
     end
   end
 
+  def on_text?
+    !!position&.on_text?
+  end
+
+  def on_image?
+    !!position&.on_image?
+  end
+
   def supported?
     for_commit? || self.noteable.has_complete_diff_refs?
   end