Add DeepInfra embeddings integration with tests and examples, better exception handling for Deep Infra LLM (#5854)

#### Who can review?

Tag maintainers/contributors who might be interested:
  @hwchase17 - project lead
  - @agola11

---------

Co-authored-by: Yessen Kanapin <yessen@deepinfra.com>

tests/integration_tests/embeddings/test_deepinfra.py

@@ -0,0 +1,19 @@
+"""Test DeepInfra API wrapper."""
+
+from langchain.embeddings import DeepInfraEmbeddings
+
+
+def test_deepinfra_call() -> None:
+    """Test valid call to DeepInfra."""
+    deepinfra_emb = DeepInfraEmbeddings(model_id="sentence-transformers/clip-ViT-B-32")
+    r1 = deepinfra_emb.embed_documents(
+        [
+            "Alpha is the first letter of Greek alphabet",
+            "Beta is the second letter of Greek alphabet",
+        ]
+    )
+    assert len(r1) == 2
+    assert len(r1[0]) == 512
+    assert len(r1[1]) == 512
+    r2 = deepinfra_emb.embed_query("What is the third letter of Greek alphabet")
+    assert len(r2) == 512

tests/integration_tests/llms/test_deepinfra.py

@@ -0,0 +1,10 @@
+"""Test DeepInfra API wrapper."""
+
+from langchain.llms.deepinfra import DeepInfra
+
+
+def test_deepinfra_call() -> None:
+    """Test valid call to DeepInfra."""
+    llm = DeepInfra(model_id="google/flan-t5-small")
+    output = llm("What is 2 + 2?")
+    assert isinstance(output, str)