consider all responseValidations that start with "res" or "head", not only those that start with "res." or "head." in REST actions

[johannesloher]

Currently, for REST actions, only items of responseValidationwhich start with "res." or "head." are considered. This is done so that the two different validation types can be distinguished. However, Sometimes it is useful to access res or head in a different way, e.g. with brackets if res is an array: `responseValidation: 'res[0] === "foo"'.

For that reason, all validations that start with "res" or "head" respectively should be considered.