Add plugin to display message when no data is rendered

[tgentet-obrien]

Add the following to loadScript:

window.Chart.plugins.register({
    afterDraw: function (chart) {
        if (chart.data.datasets.length === 0 || chart.data.datasets[0].data.length === 0) {
            // No data is present
            let ctx = chart.chart.ctx;
            let width = chart.chart.width;
            let height = chart.chart.height;
            chart.clear();

            ctx.save();
            ctx.textAlign = "center";
            ctx.textBaseline = "middle";
            ctx.font = "16px normal 'Helvetica Nueue'";
            ctx.fillText("No data to display", width / 2, height / 2);
            ctx.restore();
        }
    }
});

This displays text instead of just having a blank box, it looks better when used on Experience Sites, so customers don't think the chart is broken and just looks a little more professional.

This was not my idea, it was @boriskzd who posted this, on a chartjs/Chart.js#3745