Make the otelhttp Transport handle protocol switching

[MrAlias]

Fixes #1329

The otelhttp.Transport type wraps the response body returned from the HTTP request. Response bodies from requests to protocol switch (e.g. WebSockets, h2c) will contain a writable response body implementing the io.ReadWriteCloser interface. This interface needs to continue being satisfied so these new protocols can write directly to the opened TCP socket. This changes the wrappedBody type to implement an io.ReadWriteCloser and appropriately scopes the response body implementation to match the original (removing the Write method of the wrappedBody when it is not supported).

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (main@e3db96c). Click here to learn what that means.
The diff coverage is 100.0%.

@@          Coverage Diff           @@
##             main   #1628   +/-   ##
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  Coverage        ?   69.5%           
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  Files           ?     127           
  Lines           ?    5448           
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  Hits            ?    3787           
  Misses          ?    1519           
  Partials        ?     142           

Impacted Files	Coverage Δ
instrumentation/net/http/otelhttp/transport.go	94.6% <100.0%> (ø)