A number of small improvements can be made to the CommunityConfiguration form used for featured templates:
- When entering a template and selecting the autocomplete value, the 'part' already typed remains in the input (not fixed, but upstream: T398428: PageTitlesControl does not clear input when selecting a title from the dropdown)
- JS warnings when loading form
- 'front-end' validation (i.e. T397593: Prevent multiple 'titles' inputs for featured templates)
- Add missing i18n messages