Add function for movie accepts negative rating

[nus-pe-bot]

Command used: add /movie potato /rating -10 /date 08-12-2020 /genre romance

Expected: Exception/error message thrown

Actual: Accepted input

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_{[original: nus-cs2113-AY2223S1/pe-interim#745] [original labels: severity.Medium type.FunctionalityBug]}

[naz019]

Team's Response

No details provided by team.

Duplicate status (if any):

Duplicate of #671