modified retrievers to support optional node labels

[gurveervirk]

Description

Note

Adds support for optional node label filtering to the external retrievers: WeaviateNeo4jRetriever, QdrantNeo4jRetriever, and PineconeNeo4jRetriever.

• Introduces an optional node_label parameter to the retriever constructors and models.
• Updates Cypher query generation to use the label in the MATCH clause if provided.
• Passes node_label from the retriever to the query logic.
• Addresses issue Add an optional node label in external retrievers to optimize the match query #344.

Type of Change

• New feature
• Bug fix
• Breaking change
• Documentation update
• Project configuration change

Complexity

Note

Please provide an estimated complexity of this PR of either Low, Medium or High

Complexity: Medium

How Has This Been Tested?

• Unit tests
• E2E tests
• Manual tests

Checklist

The following requirements should have been met (depending on the changes in the branch):

• Documentation has been updated
• Unit tests have been updated
• E2E tests have been updated
• Examples have been updated
• New files have copyright header
• CLA (https://neo4j.com/developer/cla/) has been signed
• CHANGELOG.md updated if appropriate

[stellasia]

Hi @gurveervirk ,

Thank you for taking this issue and submitting a PR. Before we can process, you need to sign our CLA. Can I ask you to take a look at the following information and let us know when it's done ? https://neo4j.com/developer/cla/#sign-cla

We will then be able to add you to the list of "approved" users and proceed with the review.

Thank you.