fix(backtest): pass data_source to validate_preview_inputs in validate_current_scenario

app/pages/backtests.py

@@ -722,6 +722,7 @@ def _render_backtests_page(workspace_id: str | None = None) -> None:
                     loan_amount=float(loan_input.value or 0.0),
                     margin_call_ltv=float(ltv_input.value or 0.0),
                     entry_spot=entry_spot,
+                    data_source=str(data_source_select.value),
                 )
             except (ValueError, KeyError) as exc:
                 return str(exc)