fix: Address CI failures - type annotations, lint, security

- Fix TypeAlias annotation in elasticsearch/types.py using TYPE_CHECKING
- Add 'elasticsearch' to _MissingProvider Literal type in base.py
- Remove unused variable in test_client.py
- Add usedforsecurity=False to MD5 hash in config.py for security check

Co-Authored-By: João <joao@crewai.com>

src/crewai/rag/elasticsearch/config.py

@@ -61,7 +61,7 @@ def _default_embedding_function() -> ElasticsearchEmbeddingFunctionWrapper:
             import hashlib
             import struct
             
-            hash_obj = hashlib.md5(text.encode())
+            hash_obj = hashlib.md5(text.encode(), usedforsecurity=False)
             hash_bytes = hash_obj.digest()
             
             vector = []