Adding Metadata Filtering support for UpstashVectorStore (#12054)

docs/examples/vector_stores/UpstashVectorDemo.ipynb

...-stores-upstash/llama_index/vector_stores/upstash/base.py

...r_stores/llama-index-vector-stores-upstash/pyproject.toml

...s/llama-index-vector-stores-upstash/tests/test_upstash.py