Parse extension host callbacks on 24h2 and 25h2

[yardenshafir]

Summary

1. Extension host structures changed in 25H2, and can potentially support more than one host table per host (though right now only one table is used for each host). Adding EX_HOST_ENTRY_V2 and other required structures to correctly parse extension on 25H2.
2. Since 24H2, there is an additional call in ExRegisterExtension that breaks byte pattern search for ExpFindHost. In 25H2. In 25H2, the call from ExRegisterExtension is to a new function ExpFindCompatibleHost, so another search is needed to find ExpFindHost. The PR fixes the search for both cases.