test.Client is incorrectly using isinstance check instead of issubclass

[jace]

The documentation for werkzeug.test.Client says it expects a subclass of TestResponse, failing which it will construct the subclass:

werkzeug/src/werkzeug/test.py

Lines 778 to 780 in 5ff0a57

	:param response_wrapper: A :class:`.Response` class to wrap response data with.
	Defaults to :class:`.TestResponse`. If it's not a subclass of ``TestResponse``,
	one will be created.

However, the implementation is using isinstance instead of issubclass:

werkzeug/src/werkzeug/test.py

Lines 812 to 817 in 5ff0a57

	elif not isinstance(response_wrapper, TestResponse):
	response_wrapper = type(
	"WrapperTestResponse",
	(TestResponse, response_wrapper), # type: ignore
	{},
	)

The problem was introduced in commit 669323c (specific lines) so it's been around since the 2.0 release.