Fix SelectiveChannel response copy for non-reflectable messages

[cw20050111-prog]

Fix SelectiveChannel handling of non-reflectable responses such as RedisResponse.

Changes:

• Add a non-reflectable message hook for same-type response copying without protobuf reflection.
• Keep the existing reflection Swap path for normal protobuf messages.
• Provide a protobuf 34-compatible MessageCreator so Message::New() works for non-reflectable responses.
• Add a Redis-backed SelectiveChannel regression test.

Testing:

• bazel --output_base=/private/tmp/brpc3372_linquickdev_bazel_output test //test:brpc_channel_unittest --test_filter=ChannelTest.selective_channel_supports_nonreflectable_response --test_timeout=30 --test_output=errors --macos_sdk_version=15.2 --symlink_prefix=/ --nocache_test_results