Fix Tests (#1904)

* Revert "chore: exclude semantic search crate"

This reverts commit 6fe1e3ebf0db9a1e6571149bc1bfde50931f4165.

* fix(semantic_search): Fix VectorIndex is_empty implementation

The VectorIndex.is_empty() method was incorrectly checking if ef_construction
was equal to 100 to determine if the index was empty. This approach was
unreliable and caused test failures. This change adds a proper counter to
track the number of elements in the index and updates is_empty() to check
this counter instead.

🤖 Assisted by [Amazon Q Developer](https://aws.amazon.com/q/developer)

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Co-authored-by: Kenneth Sanchez V <[email protected]>

Author: 2 people