fix: default values in subordinate entities based on static_filtering, add: button visibility callbacks in entities' forms

model/bot_entity.py

@@ -258,7 +258,7 @@ class BotEntity[CreateSchemaType: BaseModel, UpdateSchemaType: BaseModel](
                 condition = column(sfilt.field_name).isnot(None)
             else:
                 condition = None
-            if condition:
+            if condition is not None:
                 select_statement = select_statement.where(condition)
         return select_statement