Resolving of Backend template names is not correct for content elements with underscore in name

[CarlosAgrelis]

mask.json

{
    "tt_content": {
        "elements": {
            "test_element": {
                "color": "#000000",
                "columns": [
                    "tx_mask_name_test"
                ],
                "description": "Element with \"_\" in name",
                "icon": "",
                "key": "test_element",
                "label": "Test Element",
                "labels": [
                    "Name Test"
                ],
                "shortLabel": "Test Element"
            }
        },
        "sql": {
            "tx_mask_name_test": {
                "tt_content": {
                    "tx_mask_name_test": "tinytext"
                }
            }
        },
        "tca": {
            "tx_mask_name_test": {
                "config": {
                    "default": "",
                    "eval": "required,trim",
                    "is_in": "",
                    "max": "",
                    "placeholder": "",
                    "size": "",
                    "type": "input"
                },
                "exclude": "1",
                "key": "name_test"
            }
        }
    }
}

When this is exported, installed and activated. And one element is set on the page in the backend. This error is shown:

Problem is mask_export/Classes/Aggregate/BackendPreviewAggregate.php line 216:

216            \$this->view->setTemplate(ucfirst(\$this->supportedContentTypes[\$contentType]));

Suggested solution:

216            \$this->view->setTemplate(GeneralUtility::underscoredToUpperCamelCase(\$this->supportedContentTypes[\$contentType]));