params: fix default boolean params (#35997)

* fix

* update test

system/manager/manager.py

@@ -40,7 +40,7 @@ def manager_init() -> None:
   # set unset params to their default value
   for k in params.all_keys():
     default_value = params.get_default_value(k)
-    if default_value and params.get(k) is None:
+    if default_value is not None and params.get(k) is None:
       params.put(k, default_value)
 
   # Create folders needed for msgq

system/manager/test/test_manager.py

@@ -46,9 +46,10 @@ class TestManager:
     manager.main()
     for k in params.all_keys():
       default_value = params.get_default_value(k)
-      if default_value:
+      if default_value is not None:
         assert params.get(k) == default_value
     assert params.get("OpenpilotEnabledToggle")
+    assert params.get("RouteCount") == 0
 
   @pytest.mark.skip("this test is flaky the way it's currently written, should be moved to test_onroad")
   def test_clean_exit(self, subtests):