Search query var gets re-slashed in rebooted query

[dlh01]

WP_Query calls stripslashes() on the s query var when parsing searches: https://github.com/WordPress/wordpress-develop/blob/eb06a59f536692e9499b89abd3f156ff56d3075e/src/wp-includes/class-wp-query.php#L1338-L1341

ES_WP_Query mimics this behavior in \ES_WP_Query_Wrapper::parse_search(), but \ES_WP_Query_Shoehorn::reboot_query_vars() puts the original s back into the query, causing the slashed string to be returned in get_search_query() and functions relying on it like wp_get_document_title().