Add sparse float vector support

[zhengbuqian]

Milvus 2.4 has added beta support to sparse float vector to allow efficient storing, indexing and searching of such vectors. The main targeted use case is to support learned sparse models such as SPLADE and statistics based methods such as BM25.

We need to add sparse float vector to Java SDK as well. See: milvus-io/milvus#29419 (comment) for more details.

Thanks a lot for the efforts!

[yhmo]

Already done in v2.4.0