community[minor]: Support PGVector in PebbloRetrievalQA (#23874)

- **Description:** Support PGVector in PebbloRetrievalQA
  - Identity and Semantic Enforcement support for PGVector
  - Refactor Vectorstore validation and name check
  - Clear the overridden identity and semantic enforcement filters
- **Issue:** NA
- **Dependencies:** NA
- **Tests**: NA(already added)
-  **Docs**: Updated
- **Twitter handle:** [@Raj__725](https://twitter.com/Raj__725)

docs/docs/integrations/providers/pebblo/pebblo_retrieval_qa.ipynb

@@ -60,6 +60,7 @@
     "**PebbloRetrievalQA chain supports the following vector databases:**\n",
     "- Qdrant\n",
     "- Pinecone\n",
+    "- Postgres(utilizing the pgvector extension)\n",
     "\n",
     "\n",
     "**Load vector database with authorization and semantic information in metadata:**\n",