docs: revert Runtime Profile terminology to Session Template

Follow-up to the sessionTemplate() method revert -- the remaining
prose in the README and test docstrings/comments still said "Runtime
Profile", which no longer matched the actual API surface.

Author: ajma

README.md

@@ -20,7 +20,7 @@ pip uninstall google-cloud-managed-spark-connect
 ## Setup
 
 This client requires permissions to
-manage [Managed Spark Sessions and Runtime Profiles](https://cloud.google.com/dataproc-serverless/docs/concepts/iam).
+manage [Managed Spark Sessions and Session Templates](https://cloud.google.com/dataproc-serverless/docs/concepts/iam).
 
 If you are running the client outside of Google Cloud, you need to provide
 authentication credentials. Set the `GOOGLE_APPLICATION_CREDENTIALS` environment

tests/integration/test_session.py

@@ -332,7 +332,7 @@ def test_create_spark_session_with_session_template_and_user_provided_dataproc_c
     session_template_name,
     session_controller_client,
 ):
-    """Test creating a Spark session with a Runtime Profile and user-provided Dataproc configuration."""
+    """Test creating a Spark session with a session template and user-provided Dataproc configuration."""
     dataproc_config = Session()
     dataproc_config.environment_config.execution_config.ttl = {"seconds": 64800}
     dataproc_config.session_template = session_template_name

tests/unit/test_session.py

@@ -2107,7 +2107,7 @@ def test_builder_pattern_session_template_and_labels(
                 .getOrCreate()
             )
 
-            # Verify the session was created with the correct Runtime Profile and labels
+            # Verify the session was created with the correct session template and labels
             create_session_request = mock_session_controller_client_instance.create_session.call_args[
                 0
             ][