IndexPatterns Service - [x] Factor out dupe code - [x] Make function - remove - [x] make functions private - https://github.com/elastic/kibana/issues/61812 - [ ] No longer extend Array class in field list class - will address in https://github.com/elastic/kibana/issues/78378 - [x] Method to refresh field list - [x] Method to update field formatter - [x] Create index pattern via single method call