Failed to conformance for cancel-after-close-send testcase

[tsubakiky]

https://github.com/gaudiy/connect-python/actions/runs/15134600783/job/42543332402?pr=89

FAILED: Client Cancellation/HTTPVersion:2/Protocol:PROTOCOL_CONNECT/Codec:CODEC_JSON/Compression:COMPRESSION_IDENTITY/TLS:true/bidi-stream/half-duplex/cancel-after-close-send:
	expecting 0 response messages but instead got 1
---- HTTP Trace ----
 request>     0.000ms POST https://.../connectrpc.conformance.v1.ConformanceService/BidiStream HTTP/2.0
 request>             Accept-Encoding: identity
 request>             Connect-Accept-Encoding: gzip
 request>             Connect-Protocol-Version: 1
 request>             Content-Type: application/connect+json
 request>             User-Agent: connect-python/0.0.1 (Python/3.13.3 (main, Apr  9 2025, 01:39:32) [GCC 13.3.0])
 request>             X-Expect-Codec: 2
 request>             X-Expect-Compression: 1
 request>             X-Expect-Http-Method: POST
 request>             X-Expect-Http-Version: 2
 request>             X-Expect-Protocol: 1
 request>             X-Expect-Tls: true
 request>             X-Test-Case-Name: Client Cancellation/HTTPVersion:2/Protocol:PROTOCOL_CONNECT/Codec:CODEC_JSON/Compression:COMPRESSION_IDENTITY/TLS:true/bidi-stream/half-duplex/cancel-after-close-send
 request>
 request>    68.016ms message #1: prefix: flags=0, len=148
 request>             message #1: data: 148/148 bytes
 request>    92.071ms message #2: prefix: flags=0, len=43
 request>             message #2: data: 43/43 bytes
 request>    96.307ms body end
response<   297.047ms 200 OK
response<             Connect-Accept-Encoding: zstd,snappy,deflate,br,gzip
response<             Connect-Content-Encoding: gzip
response<             Content-Type: application/connect+json
response<             Server: connectconformance-referenceserver/v1.0.4
response<             Vary: Origin
response<
response<   297.048ms message #1: prefix: flags=1, len=573
response<             message #1: data: 573/573 bytes
response<   497.719ms message #2: prefix: flags=1, len=67
response<             message #2: data: 67/67 bytes
response<   497.834ms message #3: prefix: flags=3, len=26
response<             message #3: data: 26/26 bytes
response<               eos: {}
response<   497.874ms body end
--------------------

Total cases: 4282
4281 passed, 1 failed