Tooltips with dataset mode are not correctly shown

[stockiNail]

Expected Behavior

When the tooltip is shown and the dataset mode has been, I'm excepting to have the datset label in the title, and in the body all labels and their relative values.

Current Behavior

Using the CHART.JS samples (https://www.chartjs.org/samples/master/tooltips/interactions.html). I see the following:

where:

• title is JANUARY (even if I'm hovering on April) but it' should be the dataset label My First dataset
• the BODY has got the dataset label instead of the data label.

Steps to Reproduce

I haven't created any test case because it can be reproduced using the CHART.JS sample (https://www.chartjs.org/samples/master/tooltips/interactions.html)

Environment

• Chart.js version: https://www.chartjs.org/samples/master/tooltips/interactions.html where dist/master is used.
• Browser name and version: FF 82.0.2

[LeeLenaleee]

You can if you want just override the default callback in the tooltips options like this to show a corrrect tooltip for dataset mode

tooltips: {
	mode: mode,
	intersect: intersect,
	callbacks: {
		title: (tooltipItems) => {
			const item = tooltipItems[0];
			
                        if (item.chart.config.options.tooltips.mode === 'dataset') {
				return item.dataset.label || '';
			}

			return item.label;
		},
		label: (tooltipItem) => {
			if (tooltipItem.chart.config.options.tooltips.mode === 'dataset') {
				return tooltipItem.label + ': ' + tooltipItem.formattedValue || tooltipItem.formattedValue;
			}

			return tooltipItem.label + ': ' + tooltipItem.formattedValue;
		}
	},
},