Change the return type of NodeGrantDatabaseStorageInterface::checkAll() and NodeAccessControlHandler::checkAllGrants() to a bool

Let's actually fix the return type. At the moment this methods returns string numbers ie. '0' or '1'... however in node_access_view_all_nodes() we claim it's returning a bool.

In the core use-cases we are using the return value in if statements therefore I think we should update the implementation and documentation to return bools. This has come up in 📌 Deprecate node_access_view_all_nodes(). Move its functionality in NodeAccessControlHandlerInterface Needs work