T250851 enabled the client search experience to be swapped in Core. T257647 makes the new client experience available. This task captures the work to add a configuration that swaps between the old and the new.
== Acceptance criteria
- [] A new search client configuration flag is added for Latest mode (version 2) only. When set, the new search client experience is loaded. When unset, the existing search client experience is loaded. Note: this flag has nothing to do with the position of search which is determined by the server render and identical for both client experiences. This flags changes only the JavaScript and styles that are loaded. This can use the feature manager if it makes sense.
- [] Regardless of configuration, Legacy mode operates the same.
- [] T249297 is revised to include deployment instructions and a patch (-2'd initially).