fix inherited backend var deps (#2715)

* fix inherited backend var deps

* fixing the real issue with @masenf

* Revert "fix inherited backend var deps"

This reverts commit 894e3e14acff2d661a6677c7e283db456504a7b2.

* python 3.8

reflex/state.py

@@ -466,7 +466,10 @@ class BaseState(Base, ABC, extra=pydantic.Extra.allow):
                     # track that this substate depends on its parent for this var
                     state_name = cls.get_name()
                     parent_state = cls.get_parent_state()
-                    while parent_state is not None and var in parent_state.vars:
+                    while parent_state is not None and var in {
+                        **parent_state.vars,
+                        **parent_state.backend_vars,
+                    }:
                         parent_state._substate_var_dependencies[var].add(state_name)
                         state_name, parent_state = (
                             parent_state.get_name(),