No error handled when the input is massive

[nus-pe-bot]

It says that the requirement is added but it does not show up on the requirement list. Should probably handle errors when the input is too large

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_{[original: nus-cs2103-AY1920S2/pe-interim#2551]}

[yjskrs]

Team's Response

The requirement was not added due to issues with accepting the command input, and yet no error response was displayed, as was with #763.

Duplicate status (if any):

Duplicate of #763