fix : fix cardinal compile error

[foxspy]

/root/milvus/cmake_build/thirdparty/knowhere/knowhere-src/include/knowhere/index/index_factory.h:71:38: error: redefinition of 'const knowhere::IndexFactory& knowhere::index_factory_ref_HNSWfp32'

[sre-ci-robot]

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[mergify]

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For efficient project management and a seamless review process, it's essential to classify your PR correctly. Here's how:

1. If you're fixing a bug, label it as kind/bug.
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[foxspy]

/kind enhancement

[foxspy]

verified locally