Don't initialise spark progress widget if it's not supported (#1402)

## Changes
Don't initialise spark progress widget if it's not supported

## Tests
Manually

Author: ilia-db

packages/databricks-vscode/package.json

@@ -882,7 +882,7 @@
                     "databricks.connect.progress": {
                         "type": "boolean",
                         "default": true,
-                        "description": "Show PySpark progress bar when using Databricks Connect."
+                        "markdownDescription": "Show PySpark progress bar when using Databricks Connect. Requires `ipywidgets` package and `[email protected]+`."
                     },
                     "databricks.ipythonDir": {
                         "type": "string",

packages/databricks-vscode/resources/python/00-databricks-init.py

@@ -376,6 +376,9 @@ def register_spark_progress(spark, show_progress: bool):
         import ipywidgets as widgets
     except Exception as e:
         return
+    
+    if not hasattr(spark, "clearProgressHandlers") or not hasattr(spark, "registerProgressHandler"):
+        return
 
     class Progress:
         SI_BYTE_SIZES = (1 << 60, 1 << 50, 1 << 40, 1 << 30, 1 << 20, 1 << 10, 1)