Import Details Page

[bradenmacdonald]

When clicking on a previous/ongoing import from the #2523 , show the Import Details page:

https://www.figma.com/design/4wsTUbieYphB2qchIPxm10/%E2%9C%8F%EF%B8%8F-Library---Course-Authoring-v1.0--Open-edX-?node-id=14264-40335&t=6doa6ywVTLoi4sBK-4

• Report overall import status and # of blocks of each type
• List blocks that failed to import
• "View imported content" button to access the resulting collection