Added label validators (#2078)

* Added label validators

* Updated version

cvat-ui/package-lock.json

 {
   "name": "cvat-ui",
-  "version": "1.8.1",
+  "version": "1.8.2",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {

cvat-ui/package.json

 {
   "name": "cvat-ui",
-  "version": "1.8.1",
+  "version": "1.8.2",
   "description": "CVAT single-page application",
   "main": "src/index.tsx",
   "scripts": {

cvat-ui/src/components/labels-editor/common.ts

@@ -44,6 +44,11 @@ function validateParsedAttribute(attr: Attribute): void {
         + `Attribute values must be an array. Got type ${typeof (attr.values)}`);
     }
 
+    if (!attr.values.length) {
+        throw new Error(`Attribute: "${attr.name}". Attribute values array mustn't be empty`);
+    }
+
+
     for (const value of attr.values) {
         if (typeof (value) !== 'string') {
             throw new Error(`Attribute: "${attr.name}". `
@@ -62,6 +67,11 @@ export function validateParsedLabel(label: Label): void {
         + `Type of label id must be only a number or undefined. Got value ${label.id}`);
     }
 
+    if (typeof (label.color) !== 'string') {
+        throw new Error(`Label "${label.name}". `
+        + `Label color must be a string. Got ${typeof (label.color)}`);
+    }
+
     if (!label.color.match(/^#[0-9a-f]{6}$|^$/)) {
         throw new Error(`Label "${label.name}". `
         + `Type of label color must be only a valid color string. Got value ${label.color}`);