bug in rule

Signed-off-by: Matt Bruce <matt.bruce@verizon.com>

MVMCoreUI/FormUIHelpers/Rules/Rules/RuleVDSModel.swift

@@ -49,7 +49,7 @@ public class RuleVDSModel<ValueType>: VDSRuleBase {
     public override func isValid(_ formField: FormFieldProtocol) -> Bool {
         let value = formField.formFieldValue() as? ValueType
         let valid = rule.isValid(value: value)
-        if let field = fields.first, valid {
+        if let field = fields.first, !valid {
             errorMessage = [field: rule.errorMessage]
         } else {
             errorMessage = nil