Change the default of openOnFocus to true

Most behaviour, especially in detached mode, is more predictable if openOnFocus is true. I think it could be interesting to change the default, and maybe even remove the `openOnFocus: false` behaviour.

Alternatively maybe in detached mode the behaviour should always be openOnFocus: true without taking the option in account.

ref: [CR-7603]

[CR-7603]: https://algolia.atlassian.net/browse/CR-7603?atlOrigin=eyJpIjoiNWRkNTljNzYxNjVmNDY3MDlhMDU5Y2ZhYzA5YTRkZjUiLCJwIjoiZ2l0aHViLWNvbS1KU1cifQ

Start by locating the openOnFocus option and the behavior for detached mode. Resolve whether the default should change, whether false should remain supported, or whether detached mode should ignore the option; done when the chosen behavior is implemented consistently.

Written by the indexing model from the issue text.