Use a shorter version of URL helper

Some routes can use a shorter version of a helper.
That allows skipping a namespace object.

The two following helpers produce the same result.

```
app.namespace_project_error_tracking_projects_path(
  @project.namespace, @project
)

app.project_error_tracking_projects_path(
  @project
)
```

More info here
https://gitlab.com/gitlab-org/gitlab
/-/blob/v12.5.0-ee/config/application.rb#L279-291

app/views/projects/settings/operations/_error_tracking.html.haml

@@ -12,7 +12,7 @@
       = _('To link Sentry to GitLab, enter your Sentry URL and Auth Token.')
       = link_to _('More information'), help_page_path('user/project/operations/error_tracking'), target: '_blank', rel: 'noopener noreferrer'
   .settings-content
-    .js-error-tracking-form{ data: { list_projects_endpoint: namespace_project_error_tracking_projects_path(@project.namespace, @project, format: :json),
+    .js-error-tracking-form{ data: { list_projects_endpoint: project_error_tracking_projects_path(@project, format: :json),
         operations_settings_endpoint: project_settings_operations_path(@project),
         project: error_tracking_setting_project_json,
         api_host: setting.api_host,