Data validation is missing for students cards

[outlying]

Data validation and card adding process is far away from perfect but for students cards it was forgotten.

Fatal Exception: java.lang.NumberFormatException: Invalid int: ""
       at java.lang.Integer.invalidInt(Integer.java:138)
       at java.lang.Integer.parseInt(Integer.java:358)
       at java.lang.Integer.parseInt(Integer.java:334)
       at com.antyzero.cardcheck.ui.screen.addcard.AddCardActivity$onCreate$3.onClick(AddCardActivity.kt:58)

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