fix(valkey): add client_name to Valkey connection configuration

[SyedShahmeerAli12]

Related Issues

Closes #3356

Proposed Changes

Add client_name=haystack_vector_store_client to SyncGlideClientConfiguration and GlideClientConfiguration when creating standalone (non-cluster) Valkey connections.

This makes Haystack connections identifiable in monitoring tools like CLIENT LIST, Valkey Admin, and CloudWatch metrics (ElastiCache).

How did you test it

The change adds a known parameter to an existing configuration object. No logic is affected.

Notes for the reviewer

Applied to both sync and async paths for consistency.

Checklist

• I have read the contributors guidelines
• I have updated the related component(s) documentation if needed
• I have added tests for the changes I made (if applicable)
• I have updated the CHANGELOG.md file in the relevant integration folder

[github-actions]

Coverage report (valkey)

Click to see where and how coverage changed

File	Statements	Missing	Coverage	Coverage (new stmts)	Lines missing
integrations/valkey/src/haystack_integrations/document_stores/valkey
document_store.py					241, 278-279
Project Total

This report was generated by python-coverage-comment-action

[bogdankostic]

Thanks @SyedShahmeerAli12! :)