fix(validator): parameter validation list<string>|string

[soyuka]

Q	A
Branch?	4.1
License	MIT

The default type for parameters is list|string, but as soon as we got a collection we forced the validation on the All constraints, constraint that wants an array. This wraps our assertion as:

                $assertions = $assertions ? [new AtLeastOneOf([new Sequentially($assertions), new All($assertions)])] : [];

When both types may be expected. Note that if castAsArray is set, we only use the All assertion. Ping @aegypius @deguif