MDL-35297 book: replay some steps lost when book landed to core
This commit replays, conditionally, all the upgrade steps from MOODLE_19_STABLE to MOODLE_23_STABLE in the mod_book activity. That guarentees that any site using the mod_book before landing to core, no matter if it was the latest or an outdated one will upgrade perfectly to the expected current version. As a general rule, everytime one contrib plugin lands to core, its complete upgrade code must be kept, at least until the core version that introduced it, is out completely from the upgrade requirement conditions. In this case, with the missing upgrade code being added to 2.4, it will be safe to delete the upgrade steps once 2.5 (or upwards) become a requirement. Never always.