Min and MaxLength validation of TextArea do nothing

[VincentKeltjens]

Setting the values for MinLength and MaxLength do no appear to trigger the invalid state of a TextArea.

Copied from http://formio.github.io/ngFormBuilder/ and added (which is also broken by the way, but not sure if there should be an issue for this...)

{
input: true,
tableView: true,
label: "Message",
key: "message",
placeholder: "What do you think?",
prefix: "",
suffix: "",
rows: 3,
multiple: false,
defaultValue: "",
protected: false,
persistent: true,
-validate: {
required: false,
minLength: "10",
maxLength: "25",
pattern: "",
custom: ""
},
type: "textarea",
-conditional: {
show: false,
when: null,
eq: ""
},
$$hashKey: "object:21",
autofocus: false,
hidden: false,
wysiwyg: false,
clearOnHide: true,
spellcheck: true
}