[Bug] Commands that are not supposed to accept multiple inputs of the same flag can do so

[Ditzchann]

If multiple of the same flag is given for commands that only accept one, only the last one will be taken and no error is thrown
edit 1 -med Panadol - med ABC

Within the add command, some flags are allowed to be duplicated without error while some are not.
Output for
add -n Jol23 -n Johnnty 214 -p 923456314 -a 123 Clementi Ave 34 -g Male -d 2025-04-05 -c High BP

Output for
add -n Johnnty 214 -p 923456314 -a 123 Clementi Ave 34 -g Male -d 20215125 -d 2025-04-05 -c High BP

Expectation: The command should throw an error similar to how it would for -n.