Resolve mismatch between FeedbackSession and FeedbackSessionAttributes isClosed, isOpened, isInGracePeriod

[FergusMok]

Currently, there's a mismatch in behavior of the methods during the migration. FeedbackSession only takes into account endTime, but the original method takes into account graceTime, deadlineExtensions and endTime.

https://github.com/TEAMMATES/teammates/blob/d6c67fc9dd31c36f196be454a22cce955e1c8229/src/main/java/teammates/storage/sqlentity/FeedbackSession.java#L454-L477

https://github.com/TEAMMATES/teammates/blob/d6c67fc9dd31c36f196be454a22cce955e1c8229/src/main/java/teammates/common/datatransfer/attributes/FeedbackSessionAttributes.java#L318-L344

The actual behavior should instead use these methods: https://github.com/TEAMMATES/teammates/blob/d6c67fc9dd31c36f196be454a22cce955e1c8229/src/main/java/teammates/storage/sqlentity/FeedbackSession.java#L486-L511

Impact of bug During the migration, due to similarity in names, some migrated actions are utilizing the wrong method.

Suggested change

1. As the FeedbackSessionAttributes did not need a separate isXXXGivenExtendedDeadline set of methods, a suggestion is to rename them inFeedbackSession and make the method signatures match the set of methods in FeedbackSessionAttributes.
2. Implement additional unit tests if need be.

[franko1508]

Can I work on this issue with a team for a class project?

[arnav-goel05]

Hey @FergusMok, was interested to solve the issue. Was wondering if its still available?