Don't blow up if fields are missing

Sometimes we don't have data (i.e., no bids/asks, no market price) for
contracts, and rather than blowing up we should just continue gracefully

thetagang/portfolio_manager.py

@@ -1468,7 +1468,7 @@ def fallback_minimum_price() -> float:
                     console.print(
                         "[yellow]Error occurred when trying to roll position. Continuing anyway...",
                     )
-            except RuntimeError:
+            except (RuntimeError, RequiredFieldValidationError):
                 console.print_exception()
                 console.print(
                     "[yellow]Error occurred when trying to roll position. Continuing anyway...",