Migration partial failure case: some legacy libraries successfully migrated, some failed

This is a placeholder issues for spec/designs to cover the case where some legacy libraries were successfully migrated, while some others could not be. This case was discussed at the content libraries delivery team sync today.

This ticket will provide spec/designs to ensure the user has a clear indication of which libraries failed to migrate. It may be pushed to post-Ulmo, in which case the Ulmo behavior should be (from https://github.com/openedx/frontend-app-authoring/issues/2169):

For any cases that result in unclear state for users, or content that is moved but not organized into collections, I think deleting all content from the failed migration and returning legacy libraries (and the courses that reference that content) are returned to a state as if no migration was attempted.

Start by reading the migration behavior described here and the referenced frontend-app-authoring issue #2169, then review the linked content libraries delivery discussion. Define the partial-failure states and the user indication required for each; done means the resulting specification or design covers successful and failed libraries, including the proposed post-Ulmo rollback behavior.