Pull request: 3684 validate client id in the mobileconfig form

Closes #3684

Squashed commit of the following:

commit 78e9862f7a06262f91c28d6ddcc10512560eedae
Author: Ildar Kamalov <ik@adguard.com>
Date:   Fri Oct 15 14:39:36 2021 +0300

    fix build

commit 3ed4ee69590f238396dd3aab2b62f110baa6d681
Author: Ildar Kamalov <ik@adguard.com>
Date:   Fri Oct 15 13:39:12 2021 +0300

    client: validate client id in the mobileconfig form

client/src/helpers/validators.js

@@ -83,6 +83,21 @@ export const validateClientId = (value) => {
     return undefined;
 };
 
+/**
+ * @param value {string}
+ * @returns {undefined|string}
+ */
+export const validateConfigClientId = (value) => {
+    if (!value) {
+        return undefined;
+    }
+    const formattedValue = value.trim();
+    if (formattedValue && !R_CLIENT_ID.test(formattedValue)) {
+        return 'form_error_client_id_format';
+    }
+    return undefined;
+};
+
 /**
  * @param value {string}
  * @returns {undefined|string}