filter allows non alphanumeric inputs

[nus-pe-bot]

video:https://raw.githubusercontent.com/nus-cs2103-AY2324S2/pe/master/files/d6be3724-1db8-4ef1-9144-c25edca8fe04.mp4

Filter command allows inputs that are not alphanumeric. Since tags need to be alphanumeric values, it would be better to allow only alphanumeric values into filter command.

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_{[original: nus-cs2103-AY2324S2/pe-interim#5566] [original labels: severity.Low type.FeatureFlaw]}

[ziiqii]

Team's Response

The feature is working as intended, and what was shown in the video is expected behavior.

Furthermore, the software does not fail or produce any errors. As such, this is not a bug.

Duplicate status (if any):

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