API: missing error handling for empty 802.1x user in adding wifi profile

[shaoboon]

Describe the bug
POST api/v1/amt/networkSettings/wireless/profile/$GUID with 802.1x authentication but with missing username will get general error instead of a proper input validation error

{"error":"general error","message":"general error"}

To Reproduce
Steps to reproduce the behavior:

1. POST api/v1/amt/networkSettings/wireless/profile/$GUID with 802.1x authentication but with missing username

Expected behavior
should return proper input validation error

Screenshots
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Desktop (please complete the following information):

• OS: [e.g. iOS]
• Browser [e.g. chrome, safari]
• Version [e.g. 22]

Smartphone (please complete the following information):

• Device: [e.g. iPhone6]
• OS: [e.g. iOS8.1]
• Browser [e.g. stock browser, safari]
• Version [e.g. 22]

Additional context
Add any other context about the problem here.