Saving in the backend doesn't trigger setUrlPath

[tschallacka]

When saving in the backend, https://github.com/EmicoEcommerce/Magento2AttributeLanding/blob/master/src/Model/LandingPage.php#L165 doesn't get called, but
https://github.com/EmicoEcommerce/Magento2AttributeLanding/blob/master/src/Controller/Adminhtml/Page/Save.php#L136
setData via a call from $this->dataObjectHelper->populateWithArray($landingPage, $data, LandingPageInterface::class);

setData needs to be overwritten to catch the url key being changed and then the trim applied.

See vendor/magento/framework/Api/DataObjectHelper.php:125

if ($dataObject instanceof \Magento\Framework\Model\AbstractModel) {
            $simpleData = array_filter($data, static function ($e) {
                return is_scalar($e) || is_null($e);
            });
            if (isset($simpleData['id'])) {
                $dataObject->setId($simpleData['id']);
                unset($simpleData['id']);
            }
            $simpleData = array_intersect_key($simpleData, $setMethods);
            $dataObject->addData($simpleData);
            $data = array_diff_key($data, $simpleData);
            if (\count($data) === 0) {
                return $this;
            }
        }

See vendor/magento/framework/DataObject.php:53

    /**
     * Add data to the object.
     *
     * Retains previous data in the object.
     *
     * @param array $arr
     * @return $this
     */
    public function addData(array $arr)
    {
        if ($this->_data === []) {
            $this->setData($arr);
            return $this;
        }

        foreach ($arr as $index => $value) {
            $this->setData($index, $value);
        }
        return $this;
    }
    ```