API returns no error when asking for non existing tab using method getfields()

Description

API returns no error when asking for non existing tab using method getfields().

Distribution Name and Version

Whatever is running demo.fusiondirectory.org.

FusionDirectory Version

1.2

Plugin with the defect

Web service

PHP version used

Whatever is running demo.fusiondirectory.org.

Origin of php packages

Whatever is running demo.fusiondirectory.org.

Steps to Reproduce

1. Call method getfields: {'id': '123', 'method': 'getfields', 'params': ['1kl6phb0evov24vfasiv5p2s32', 'USER', None, 'foobar']})
2. Observe answer with no error: {'result': {'sections_order': ['main'], 'sections': {'main': {'attrs': [], 'attrs_order': [], 'name': 'Plugin'}}}, 'id': '123', 'error': None}

Expected behavior:

I expect an error telling me that 'foobar' is not a valid tab name.

Actual behavior:

I'm not told that 'foobar' is not a valid tab name.

Reproduces how often: 100%