Add dbutils/remote to the user agent of calls made through the RemoteDbUtils client. (#1070)

## What changes are proposed in this pull request?

Simple PR adding `dbutils/remote` to the user agent of calls made
through the `RemoteDbUtils` client.

## How is this tested?

Unit + Integration tests.

NO_CHANGELOG=true

Author: renaudhartert-db

databricks/sdk/dbutils.py

@@ -210,7 +210,11 @@ def __init__(self) -> None:
 class RemoteDbUtils:
 
     def __init__(self, config: "Config" = None):
-        self._config = Config() if not config else config
+        # Create a shallow copy of the config to allow the use of a custom
+        # user-agent while avoiding modifying the original config.
+        self._config = Config() if not config else config.copy()
+        self._config.with_user_agent_extra("dbutils", "remote")
+
         self._client = ApiClient(self._config)
         self._clusters = compute_ext.ClustersExt(self._client)
         self._commands = compute.CommandExecutionAPI(self._client)

tests/test_dbutils.py

@@ -290,3 +290,12 @@ def test_dbutils_proxy_overrides(dbutils, mocker, restorable_env):
         return_value="test_cluster_id",
     )
     assert dbutils.notebook.entry_point.getDbutils().notebook().getContext().notebookPath().get() == "test_source_file"
+
+
+def test_dbutils_adds_user_agent(config):
+    from databricks.sdk.dbutils import RemoteDbUtils
+
+    # Create dbutils and check that user-agent includes sdk-feature/dbutils
+    dbutils = RemoteDbUtils(config)
+
+    assert "dbutils/remote" in dbutils._config.user_agent