Fixes to form validation process

Fixes hardening measure introduced in joomla#23716

libraries/src/Form/Form.php

@@ -182,9 +182,9 @@ protected function bindLevel($group, $data)
     }
 
     /**
-     * Return all errors, if any.
+     * Return Exceptions thrown during the form validation process.
      *
-     * @return  \Exception[]  Array of error messages or RuntimeException objects.
+     * @return  \Exception[]
      *
      * @since   1.7.0
      */
@@ -1134,6 +1134,7 @@ public function validate($data, $group = null)
                 // The field returned false from setup and shouldn't be included in the page body - yet we received
                 // a value for it. This is probably some sort of injection attack and should be rejected
                 $this->errors[] = new \RuntimeException(Text::sprintf('JLIB_FORM_VALIDATE_FIELD_INVALID', $key));
+                $return         = false;
             }
         }