test: fix Response204WithBody flake (#12473)
test: fix Response204WithBody flake (#12473)

Fixes https://github.com/envoyproxy/envoy/issues/12459

Signed-off-by: Matt Klein <684e4e870ef5a243d6d0345280f09d95db603639@lyft.com>
envoyproxy/envoy,envoyproxy/envoy,envoyproxy/envoy,lizan/envoy,envoyproxy/envoy-wasm,lizan/envoy,envoyproxy/envoy-wasm,envoyproxy/envoy,envoyproxy/envoy-wasm,lyft/envoy,lyft/envoy,lizan/envoy,envoyproxy/envoy,envoyproxy/envoy-wasm,envoyproxy/envoy,lyft/envoy,envoyproxy/envoy-wasm,lizan/envoy,envoyproxy/envoy,lyft/envoy,envoyproxy/envoy-wasm,envoyproxy/envoy,envoyproxy/envoy,envoyproxy/envoy,lizan/envoy,envoyproxy/envoy-wasm,envoyproxy/envoy,lizan/envoy,lyft/envoy,lyft/envoy,envoyproxy/envoy