- Updated `SearchRequest.java` to make the class non-final.
- Added `MilvusSearchRequest` with specific Milvus parameters such as `nativeExpression` and `searchParamsJson`.
- Modified `doSimilaritySearch` method in `MilvusVectorStore` to handle these new fields from `MilvusSearchRequest`.
Add unit tests for MilvusVectorStore and MilvusSearchRequest
Introduce comprehensive unit tests to validate the functionality of MilvusVectorStore and MilvusSearchRequest, including scenarios for native and filter expressions. Refactor MilvusVectorStore to improve filter expression handling by introducing a helper method for converted expressions.
Add detailed documentation for MilvusSearchRequest usage
Introduced sections explaining MilvusSearchRequest's parameters, `nativeExpression`, and `searchParamsJson`, with examples for enhanced clarity. This update provides guidance on leveraging Milvus-specific features for precise filtering and optimal search performance.
Signed-off-by: waileong <wai_leong1015@hotmail.com>