Update TODO about dashboard installation retry on InternalError (#2338)

## Changes
Update TODO about dashboard installation retry on `InternalError` to be
more descriptive and actionable.

### Linked issues
Resolves #2172
Resolves #2173
Resolves #2198

Author: JCZuurmond

src/databricks/labs/ucx/install.py

@@ -591,8 +591,9 @@ def _handle_existing_dashboard(self, dashboard_id: str, display_name: str, paren
             return None  # Recreate the dashboard if it's reference is corrupted (manually)
         return dashboard_id  # Update the existing dashboard
 
-    # TODO: Confirm the assumption below is correct
-    # An InternalError may occur when the dashboard is being published and the database does not exists
+    # TODO: @JCZuurmond: wait for dashboard team to fix the error below,
+    # then update the retry decorator and document why this is needed
+    # databricks.sdk.errors.platform.InternalError: A database error occurred during import-dashboard-new
     @retried(on=[InternalError], timeout=timedelta(minutes=4))
     def _create_dashboard(self, folder: Path, *, parent_path: str) -> None:
         """Create a lakeview dashboard from the SQL queries in the folder"""