Fix httpx deprecation warnings

[simonw]

Lots of these: https://github.com/simonw/datasette/actions/runs/8258529260/job/22590924898

  /opt/hostedtoolcache/Python/3.12.2/x64/lib/python3.12/site-packages/httpx/_client.py:1426:
  DeprecationWarning: The 'app' shortcut is now deprecated. Use the explicit style 'transport=ASGITransport(app=...)' instead.

And:

  /opt/hostedtoolcache/Python/3.12.2/x64/lib/python3.12/site-packages/httpx/_client.py:1559:
DeprecationWarning: Setting per-request cookies=<...> is being deprecated, because the expected behaviour on cookie persistence is ambiguous. Set cookies directly on the client instance instead.

[simonw]

I can handle both of these in the datasette.client class, such that I don't have to change how dozens of tests that use datasette.client.get(..., cookie=...) work across many different plugins.

datasette/datasette/app.py

Lines 1920 to 1969 in 8b6f155

	class DatasetteClient:
	def __init__(self, ds):
	self.ds = ds
	self.app = ds.app()
	def actor_cookie(self, actor):
	# Utility method, mainly for tests
	return self.ds.sign({"a": actor}, "actor")
	def _fix(self, path, avoid_path_rewrites=False):
	if not isinstance(path, PrefixedUrlString) and not avoid_path_rewrites:
	path = self.ds.urls.path(path)
	if path.startswith("/"):
	path = f"http://localhost{path}"
	return path
	async def get(self, path, **kwargs):
	async with httpx.AsyncClient(app=self.app) as client:
	return await client.get(self._fix(path), **kwargs)
	async def options(self, path, **kwargs):
	async with httpx.AsyncClient(app=self.app) as client:
	return await client.options(self._fix(path), **kwargs)
	async def head(self, path, **kwargs):
	async with httpx.AsyncClient(app=self.app) as client:
	return await client.head(self._fix(path), **kwargs)
	async def post(self, path, **kwargs):
	async with httpx.AsyncClient(app=self.app) as client:
	return await client.post(self._fix(path), **kwargs)
	async def put(self, path, **kwargs):
	async with httpx.AsyncClient(app=self.app) as client:
	return await client.put(self._fix(path), **kwargs)
	async def patch(self, path, **kwargs):
	async with httpx.AsyncClient(app=self.app) as client:
	return await client.patch(self._fix(path), **kwargs)
	async def delete(self, path, **kwargs):
	async with httpx.AsyncClient(app=self.app) as client:
	return await client.delete(self._fix(path), **kwargs)
	async def request(self, method, path, **kwargs):
	avoid_path_rewrites = kwargs.pop("avoid_path_rewrites", None)
	async with httpx.AsyncClient(app=self.app) as client:
	return await client.request(
	method, self._fix(path, avoid_path_rewrites), **kwargs
	)