fix(vertexai): support generative model chat session tracing (#2689)

Author: galkleinman

packages/opentelemetry-instrumentation-vertexai/opentelemetry/instrumentation/vertexai/__init__.py

@@ -41,6 +41,13 @@
         "span_name": "vertexai.generate_content_async",
         "is_async": True,
     },
+    {
+        "package": "vertexai.generative_models",
+        "object": "ChatSession",
+        "method": "send_message",
+        "span_name": "vertexai.send_message",
+        "is_async": False,
+    },
     {
         "package": "vertexai.preview.generative_models",
         "object": "GenerativeModel",
@@ -55,6 +62,13 @@
         "span_name": "vertexai.generate_content_async",
         "is_async": True,
     },
+    {
+        "package": "vertexai.preview.generative_models",
+        "object": "ChatSession",
+        "method": "send_message",
+        "span_name": "vertexai.send_message",
+        "is_async": False,
+    },
     {
         "package": "vertexai.language_models",
         "object": "TextGenerationModel",