fix(spec): validation errors formatting (#9687)

Co-authored-by: Enrico Bottacin <enrico.bottacin@gmail.com>
Co-authored-by: Vladimír Gorej <vladimir.gorej@gmail.com>

src/core/plugins/spec/selectors.js

@@ -496,11 +496,12 @@ export const validationErrors = (state, pathMethod) => {
 
   paramValues.forEach( (p) => {
     let errors = p.get("errors")
-    if ( errors && errors.count() ) {
-      errors.forEach( e => result.push(e))
+    if (errors && errors.count()) {
+      errors
+        .map((e) => (Map.isMap(e) ? `${e.get("propKey")}: ${e.get("error")}` : e))
+        .forEach((e) => result.push(e))
     }
   })
-
   return result
 }