Extract OpenAI API retry handler and unify ADA embeddings calls. (#3191)

* Extract retry logic, unify embedding functions

* Add some docstrings

* Remove embedding creation from API manager

* Add test suite for retry handler

* Make api manager fixture

* Fix typing

* Streamline tests

tests/test_local_cache.py

@@ -21,7 +21,7 @@ def LocalCache():
 @pytest.fixture
 def mock_embed_with_ada(mocker):
     mocker.patch(
-        "autogpt.memory.local.create_embedding_with_ada",
+        "autogpt.memory.local.get_ada_embedding",
         return_value=[0.1] * EMBED_DIM,
     )