ChartPanel should use Double instead of Long as width/height property

Class: com.onehippo.cms7.reports.plugins.chart.ChartPanel#onRenderProperties uses long for width and that should be (like in other panels) a double property. This is also documented as such (https://documentation.bloomreach.com/14/library/enterprise/enterprise-features/content-reports/configure-content-reports.html)

    if (config.getString(CONFIG_WIDTH) != null) {
            properties.put("width", config.getLong(CONFIG_WIDTH));
     }