Lost items disappear after edit

[nus-pe-script]

Describe the bug
Editing number of quantity removes lost items from list

To Reproduce
Steps to reproduce the behavior:

1. Enter 'Lost 1 q/10'
2. 'lost&found'
3. 'edit 1 q/1'
4. 'lost&found'

Expected behavior
Lost items remains in the lost&found list

Screenshots
If applicable, add screenshots to help explain your problem.

Additional context
Add any other context about the problem here.

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Reported by: @kennethcsj
Severity: High

_{[original: nusCS2113-AY1819S1/pe-1#546]}

[HeHaowei]

fix, thanks