Python: [BREAKING] Python: move Azure AI embeddings to Foundry (#5056)

* renamed AzureAIINferenceEmbeddings and lazy load azure-cosmos and env var rename

* updated coverage

* fix readme

python/packages/core/tests/core/test_azure_namespace.py

@@ -0,0 +1,10 @@
+# Copyright (c) Microsoft. All rights reserved.
+
+from agent_framework_azure_cosmos import CosmosHistoryProvider
+
+import agent_framework.azure as azure
+
+
+def test_azure_namespace_exposes_cosmos_history_provider() -> None:
+    assert azure.CosmosHistoryProvider is CosmosHistoryProvider
+    assert "CosmosHistoryProvider" in dir(azure)