Multiple Datasets in tooltip bug

### Expected behavior

I'm trying to make the tooltip group all datasets under the same x axis but it is not working. I am using ```interaction: { mode: "index" } ```. The expected behaviour is suppose to show the correct datasets for each x axis.

### Current behavior

It is showing mixed datasets in each of the tooltips, which is incorrect.

### Reproducible sample

https://codepen.io/dza48/pen/WNzmymw

### Optional extra steps/info to reproduce

_No response_

### Possible solution

_No response_

### Context

_No response_

### chart.js version

v3.8.2

### Browser name and version

_No response_

### Link to your project

_No response_