Make mypy pass on our tests (#9648)

* make mypy pass on our tests

* fix grammar

mypy.ini

@@ -1,8 +1,14 @@
 [mypy]
-# Removing this exclude setting is being tracked by
-# https://github.com/certbot/certbot/issues/7909.
-exclude = .*/_internal/tests/
 ignore_missing_imports = True
 warn_unused_ignores = True
 show_error_codes = True
 disallow_untyped_defs = True
+
+# Using stricter settings here is being tracked by
+# https://github.com/certbot/certbot/issues/9647.
+[mypy-*._internal.tests.*]
+# By default, mypy prints notes without erroring about any type annotations it
+# finds in untyped function bodies when check_untyped_defs is false. Disabling
+# this "error" code removes this visual noise.
+disable_error_code = annotation-unchecked
+disallow_untyped_defs = False