List column number type was falling back to text

Since custom list column types an exception is thrown for unknowns. This makes number known.
Fixes #2438

modules/backend/widgets/Lists.php

@@ -912,6 +912,14 @@ class Lists extends WidgetBase
         return htmlentities($value, ENT_QUOTES, 'UTF-8', false);
     }
 
+    /**
+     * Process as number, proxy to text
+     */
+    protected function evalNumberTypeValue($record, $column, $value)
+    {
+        return $this->evalTextTypeValue($record, $column, $value);
+    }
+
     /**
      * Process as partial reference
      */