Fix: boolean casting

[haddowg]

This PR fixes two issues related to request validation.

• If a parameter is not null but "falsey" such as 0 the parameter it is not validated this PR corrects this and updates the tests

• It is currently not possible to validate "boolean" type parameters as the assertion will always fail since the string type value from the request parameter is not cast to boolean. The data (string) must match the type: boolean This PR casts true and false string values only to the appropriate boolean, and adds test coverage