Fixed a TypeScript nullability narrow in the `MergeAdvanceNotice` component, safely handling a potential null checkout value. This is a targeted type-safety fix for the integration branch advance banner. Fusion-Task-Id: FN-5447
Fixed a TypeScript nullability narrow in the `MergeAdvanceNotice` component, safely handling a potential null checkout value. This is a targeted type-safety fix for the integration branch advance banner. Fusion-Task-Id: FN-5447