TBA Course

[avery-chung]

For course with TBA time session, and also concrete time session:

1. If the first session is of TBA, no options to swap to concrete time session
2. If the first session is of concrete time, no options to swap to TBA session

For course with multiple TBA time session and no concrete time session:
No options to swap

[antony-hk]

It will be fixed after re-implementing the drag and drop interaction with React.