Add descriptionFrom support for nested properties

Adds support for JSON columns
descriptionFrom: name
descriptionFrom: json.name
descriptionFrom: json[name]

modules/backend/formwidgets/RecordFinder.php

@@ -290,7 +290,12 @@ public function getDescriptionValue()
             return null;
         }
 
-        return $this->relationModel->{$this->descriptionFrom};
+        // Convert array-like notation to dot notation
+        if (preg_match('/\[(.*?)\]/', $this->relationModel, $matches)) {
+            $this->descriptionFrom = str_replace(['[', ']'], ['.', ''], $this->descriptionFrom);
+        }
+
+        return data_get($this->relationModel, $this->descriptionFrom);
     }
 
     public function onFindRecord()