Charts: Adding multi series support for line charts

[grzegorz-cp]

Fixes https://github.com/Automattic/jetpack-roadmap/issues/2054

This PR depends on #40581

Proposed changes:

• update line chart to accept multiple series of data
• extend existing components to accept className prop for more flexible styling

Other information:

• Have you written new tests for your changes, if applicable?
• Have you checked the E2E test CI results, and verified that your changes do not break them?
• Have you tested your changes on WordPress.com, if applicable (if so, you'll see a generated comment below with a script to run)?

Jetpack product discussion

Does this pull request change what data or activity we track or use?

Testing instructions:

• navigate to the directory and run storybook: cd projects/js-packages/charts and pnpm run storybook
• verify that the line chart now shows multiple series in the default story
• verify that existing charts are working

[github-actions]

Are you an Automattician? Please test your changes on all WordPress.com environments to help mitigate accidental explosions.

• To test on WoA, go to the Plugins menu on a WordPress.com Simple site. Click on the "Upload" button and follow the upgrade flow to be able to upload, install, and activate the Jetpack Beta plugin. Once the plugin is active, go to Jetpack > Jetpack Beta, select your plugin, and enable the add/charts-multi-series branch.

  • For jetpack-mu-wpcom changes, also add define( 'JETPACK_MU_WPCOM_LOAD_VIA_BETA_PLUGIN', true ); to your wp-config.php file.

• To test on Simple, run the following command on your sandbox:

  bin/jetpack-downloader test jetpack add/charts-multi-series
  

  bin/jetpack-downloader test jetpack-mu-wpcom-plugin add/charts-multi-series
  

Interested in more tips and information?

• In your local development environment, use the jetpack rsync command to sync your changes to a WoA dev blog.
• Read more about our development workflow here: PCYsg-eg0-p2
• Figure out when your changes will be shipped to customers here: PCYsg-eg5-p2

[github-actions]

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