[PE-D][Tester E] Unintended deletion of contacts

[nus-pe-bot]

Let's say user adds a new contact to the list with the add command without performing the save command after.

The load command will load the list of last saved entries from local memory. The newly added contact is not reflected in this list since the save command was never performed.

However performing the undo command right after this will result in the removal of the last entry on the contact list.

Steps taken to replicate:

1. add n/user p/12345678 e/user@gmail.com a/abc avenue 4
2. load
3. undo

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Labels: type.FunctionalityBug severity.High original: volleyballkickedme/ped#5

[ChenLeiyu]

Duplicate of #287