Missing space between multiline label inside tooltip

### Expected behavior

Given this label `['Yellow', 'subTitle']`.
This will render as 2 seperate lines on the canvas.à
I would expect the tooltip to render as `Yellow, subTitle`.

### Current behavior

But currently, it results in `Yellow,subTitle` with no space after the comma.

### Reproducible sample

https://jsfiddle.net/Leelenaleee/3d50fkL9/26/

### Optional extra steps/info to reproduce

_No response_

### Possible solution

_No response_

### Context

_No response_

### chart.js version

4.4.8

### Browser name and version

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### Link to your project

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