Changes how errors are disabled in visit_comparison_expr (#11451)

It now has a better API for that. Change `copy()` -> `clean_copy()`.

mypy/checkexpr.py

@@ -2230,10 +2230,15 @@ def visit_comparison_expr(self, e: ComparisonExpr) -> Type:
 
                 # Keep track of whether we get type check errors (these won't be reported, they
                 # are just to verify whether something is valid typing wise).
-                local_errors = self.msg.copy()
-                local_errors.disable_count = 0
+                local_errors = self.msg.clean_copy()
                 _, method_type = self.check_method_call_by_name(
-                    '__contains__', right_type, [left], [ARG_POS], e, local_errors)
+                    method='__contains__',
+                    base_type=right_type,
+                    args=[left],
+                    arg_kinds=[ARG_POS],
+                    context=e,
+                    local_errors=local_errors,
+                )
                 sub_result = self.bool_type()
                 # Container item type for strict type overlap checks. Note: we need to only
                 # check for nominal type, because a usual "Unsupported operands for in"