Fix Fake Data to Have Correct Representation for entryDate and gradDate

[sophiacrennan]

Problem: The fake data has a different representation for entryDate and gradDate than the student spreadsheet the dean's gave us
Solution: Change the fake data to follow the student spreadsheet

Description: Currently, the value for entryDate and gradDate is a year. The student spreadsheet the deans gave us have entryDate as 'term year' (ex: FL 2019 FL 2018) and gradDate as two years (ex: 21/22 22/23)

Specs:

• change the representation of entryDate in fake data
• change the representation of gradDate in fake data

If blocked, contact @sophiacrennan