Resolve "do not set updated_at when creating note"

changelogs/unreleased/46930-fix-updated_at-if-created_at-is-set-note-api.yml

+---
+title: Fix updated_at if created_at is set for Note API
+merge_request:
+author:
+type: fixed

doc/api/notes.md

@@ -218,6 +218,7 @@ Parameters:
 - `id` (required) - The ID or [URL-encoded path of the project](README.md#namespaced-path-encoding)
 - `snippet_id` (required) - The ID of a snippet
 - `body` (required) - The content of a note
+- `created_at` (optional) - Date time string, ISO 8601 formatted, e.g. 2016-03-11T03:45:40Z
 ```bash
 curl --request POST --header "PRIVATE-TOKEN: 9koXpg98eAheJpvBs5tK" https://gitlab.example.com/api/v4/projects/5/snippet/11/notes?body=note
@@ -340,6 +341,7 @@ Parameters:
 - `id` (required) - The ID or [URL-encoded path of the project](README.md#namespaced-path-encoding)
 - `merge_request_iid` (required) - The IID of a merge request
 - `body` (required) - The content of a note
+- `created_at` (optional) - Date time string, ISO 8601 formatted, e.g. 2016-03-11T03:45:40Z
 ### Modify existing merge request note

lib/api/helpers/notes_helpers.rb

@@ -97,6 +97,8 @@ module API
             current_user.admin? || parent.owned_by?(current_user)
         end
+        opts[:updated_at] = opts[:created_at] if opts[:created_at]
+
         project = parent if parent.is_a?(Project)
         ::Notes::CreateService.new(project, current_user, opts).execute
       end

spec/support/shared_examples/requests/api/notes.rb

@@ -121,6 +121,7 @@ shared_examples 'noteable API' do |parent_type, noteable_type, id_name|
         expect(json_response['body']).to eq('hi!')
         expect(json_response['author']['username']).to eq(user.username)
         expect(Time.parse(json_response['created_at'])).to be_like_time(creation_time)
+        expect(Time.parse(json_response['updated_at'])).to be_like_time(creation_time)
       end
     end