Fix attribute entity (#8066)

* Bugfix entity attribute setter

* Fix tests

* Fix tests part 2

* Change filter only None

* Fix tests part 3

* Update entity.py

* Fix tests

homeassistant/helpers/entity.py

@@ -146,7 +146,7 @@ class Entity(object):
     @property
     def assumed_state(self) -> bool:
         """Return True if unable to access real state of the entity."""
-        return False
+        return None
 
     @property
     def force_update(self) -> bool:
@@ -321,7 +321,7 @@ class Entity(object):
 
         value = getattr(self, name)
 
-        if not value:
+        if value is None:
             return
 
         try: