Bump Chart.js from 2.9.4 to 4.2.1 in dashboard examples

[julien-deramond]

Description

This PR suggests to bump Chart.js version in dashboard and dashboard RTL examples from 2.9.4 to 4.2.1.

The configuration has slightly changed. There's no graphical regression; just a minor change regarding the rendering of numbers on the y-axis.

Type of changes

• Enhancement (non-breaking change)

Checklist

• I have read the contributing guidelines
• My code follows the code style of the project (using npm run lint)
• My change introduces changes to the documentation
• I have updated the documentation accordingly
• (N/A) I have added tests to cover my changes
• All new and existing tests passed

Live previews

• https://deploy-preview-38071--twbs-bootstrap.netlify.app/docs/5.3/examples/dashboard/
• https://deploy-preview-38071--twbs-bootstrap.netlify.app/docs/5.3/examples/dashboard-rtl/

[XhmikosR]

Nitpicking, it seems the the number in the tooltip is now too close

Also, what's the reason for removing the variable? We had it there so that it's explicit.

[julien-deramond]

Nitpicking, it seems the the number in the tooltip is now too close

Haven't changed anything, it's the default rendering. But I can work on it to add some spacing between the color area and the text.

Also, what's the reason for removing the variable? We had it there so that it's explicit.

My bad, thought it was useless to affect it to something never used. Rollbacked it in 35b7a21.

[julien-deramond]

Added some padding in 4f4c059. Rendering is better, thanks for pointing this out :)