fix: fixes lancedb batch handling (#1872)

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## Description
Fixes lancedb batch handling issue. Duplicated elements could appear in
the collections when duplicates happen in the same insert
batch.

## Type of Change
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- [x] Bug fix (non-breaking change that fixes an issue)
- [ ] New feature (non-breaking change that adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] Documentation update
- [ ] Code refactoring
- [ ] Performance improvement
- [ ] Other (please specify):

## Screenshots/Videos (if applicable)
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## Pre-submission Checklist
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- [x] **I have tested my changes thoroughly before submitting this PR**
- [x] **This PR contains minimal changes necessary to address the
issue/feature**
- [x] My code follows the project's coding standards and style
guidelines
- [x] I have added tests that prove my fix is effective or that my
feature works
- [x] I have added necessary documentation (if applicable)
- [x] All new and existing tests pass
- [x] I have searched existing PRs to ensure this change hasn't been
submitted already
- [x] I have linked any relevant issues in the description
- [x] My commits have clear and descriptive messages

## DCO Affirmation
I affirm that all code in every commit of this pull request conforms to
the terms of the Topoteretes Developer Certificate of Origin.


<!-- This is an auto-generated comment: release notes by coderabbit.ai
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## Summary by CodeRabbit

* **Bug Fixes**
* Improved data integrity by implementing deduplication logic to
eliminate duplicate entries and ensure only the latest version is
retained.

<sub>✏️ Tip: You can customize this high-level summary in your review
settings.</sub>

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

cognee/infrastructure/databases/vector/lancedb/LanceDBAdapter.py

@@ -193,6 +193,8 @@ class LanceDBAdapter(VectorDBInterface):
             for (data_point_index, data_point) in enumerate(data_points)
         ]
 
+        lance_data_points = list({dp.id: dp for dp in lance_data_points}.values())
+
         async with self.VECTOR_DB_LOCK:
             await (
                 collection.merge_insert("id")