Fix CONNECT always being treated as having an empty body

[bdraco]

What do these changes do?

CONNECT will only have an empty body on 2xx

fixes a mistake in #7755

Are there changes in behavior for the user?

Related issue number

Checklist

• I think the code is well written
• Unit tests for the changes exist
• Documentation reflects the changes
• If you provide code modification, please add yourself to CONTRIBUTORS.txt
  • The format is <Name> <Surname>.
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[bdraco]

I was looking at what it would take to write an end to end test for this, but it looks like there isn't anything for connect besides the http parser (test_url_connect)

I think the best option right now is a unit for the helper

[bdraco]

test failures are unrelated

started working through them

#7773

[patchback]

Backport to 3.9: 💔 cherry-picking failed — conflicts found

❌ Failed to cleanly apply af2bb1e on top of patchback/backports/3.9/af2bb1e7ad2e07948b02af0a2db55d5f8555ef6b/pr-7772

Backporting merged PR #7772 into master

1. Ensure you have a local repo clone of your fork. Unless you cloned it
   from the upstream, this would be your origin remote.
2. Make sure you have an upstream repo added as a remote too. In these
   instructions you'll refer to it by the name upstream. If you don't
   have it, here's how you can add it:

   $ git remote add upstream https://github.com/aio-libs/aiohttp.git

3. Ensure you have the latest copy of upstream and prepare a branch
   that will hold the backported code:

   $ git fetch upstream
   $ git checkout -b patchback/backports/3.9/af2bb1e7ad2e07948b02af0a2db55d5f8555ef6b/pr-7772 upstream/3.9

4. Now, cherry-pick PR Fix CONNECT always being treated as having an empty body #7772 contents into that branch:

   $ git cherry-pick -x af2bb1e7ad2e07948b02af0a2db55d5f8555ef6b

   If it'll yell at you with something like fatal: Commit af2bb1e7ad2e07948b02af0a2db55d5f8555ef6b is a merge but no -m option was given., add -m 1 as follows instead:

   $ git cherry-pick -m1 -x af2bb1e7ad2e07948b02af0a2db55d5f8555ef6b

5. At this point, you'll probably encounter some merge conflicts. You must
   resolve them in to preserve the patch from PR Fix CONNECT always being treated as having an empty body #7772 as close to the
   original as possible.
6. Push this branch to your fork on GitHub:

   $ git push origin patchback/backports/3.9/af2bb1e7ad2e07948b02af0a2db55d5f8555ef6b/pr-7772

7. Create a PR, ensure that the CI is green. If it's not — update it so that
   the tests and any other checks pass. This is it!
   Now relax and wait for the maintainers to process your pull request
   when they have some cycles to do reviews. Don't worry — they'll tell you if
   any improvements are necessary when the time comes!

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