text: Title: [Lens] Use index pattern service to load list
  Body: Part of https://github.com/elastic/kibana/issues/91715
  
  In 
  https://github.com/elastic/kibana/blob/master/x-pack/plugins/lens/public/indexpattern_datasource/loader.ts#L338-L342
  
  the list of index patterns is loaded via saved objects client.
  
  This should be replaced by using the `getIdsWithTitle` method of the index pattern service.