engine: remove the unused 'type' property from the OptCheck object

kconfig_hardened_check/engine.py

@@ -45,10 +45,6 @@ class OptCheck:
         self.state = None
         self.result = None
 
-    @property
-    def type(self):
-        return None
-
     def check(self):
         # handle the 'is present' check
         if self.expected == 'is present':