[DG] Incorrect steps in Use Case 01

[RobotWizzard]

The extension when a duplicate name is detected for Use case 01: Add a client state that the app only displays a warning and continues from step 2, which implies that the client should be successfully added.

However, this is not the case in the app. If the user tries to add a client with an identical name to another client that already exists, an error message is displayed and the client is not added.

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Mistake in use case 01:

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Result of adding 2 clients with identical names:

[nus-se-script]

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