Fix double registration of a complex type

Zend\Soap\Wsdl\ComplexTypeStrategy\DefaultComplexType::addComplexType()
stores already added classes under the methods argument `$type`.

Therefore a class with preceding backslash is treated like another complextype
than the same class without given backslash. As a result the xsd:ComplexType
definition is found twice (with exactly the same name) in the generated wsdl.
#6223 - cs (alignment)
#6223 - cs (braces on own line)
#6223 - coverage annotation
#6223 - removing unused imports
Merge branch 'hotfix/#6223-soap-registration-of-complex-type'

Close #6223