Reload scheduler after full download

Fixes invalid state where schedVer=2 but v1 scheduler active
https://forums.ankiweb.net/t/not-able-to-fix-database-error/20483

pylib/anki/collection.py

@@ -315,6 +315,8 @@ class Collection(DeprecatedNamesMixin):
             )
         self.db = DBProxy(weakref.proxy(self._backend))
         self.db.begin()
+        if after_full_sync:
+            self._load_scheduler()
 
     def set_schema_modified(self) -> None:
         self.db.execute("update col set scm=?", int_time(1000))