Use AcceptResponseHandler in goproxy https CONNECT hook

[cmoresco-stripe]

Wire up the AcceptResponseHandler to the new goproxy hook that was added in stripe/goproxy#21

This does require changing the type of the AcceptResponseHandler to include a context field, but since this handler was only added to the config ~days ago this shouldn't be disruptive.

Smokescreen takes a function that uses a smokescreenContext and wraps it in a function that takes a goproxy.ProxyCtx before passing it to the underlying goproxy, so that we don't leak any goproxy interfaces in the smokescreen API (remain eternally hopeful that we'll strip out goproxy entirely someday...)

Writing a unit test would require the new go 1.20 http.OnProxyConnectResponse to hook into the proxy connect response, and I don't think we're ready to upgrade smokescreen to go 1.20 yet, so the https logic here is not covered by unit tests.

[github-actions]

Pull Request Test Coverage Report for Build 5742065861

• 3 of 8 (37.5%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.1%) to 62.524%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
pkg/smokescreen/smokescreen.go	3	8	37.5%

Totals
Change from base Build 5681729420:	-0.1%
Covered Lines:	1303
Relevant Lines:	2084

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💛 - Coveralls

[jjiang-stripe]

ah sorry I thought I hit approve already :')

this seems reasonable to me! we're just hooking into the ConnectRespHandler functionality we added.