Charts: Allow user margin.top override when legend is positioned at top

[annacmc]

Proposed changes:

• Fix LineChart to respect user-provided margin.top when legend is positioned at top
• Fix BarChart to respect user-provided margin.top when legend is positioned at top
• Update margin calculation to use margin?.top ?? defaultMargin.top pattern
• Add test coverage for LineChart margin behavior with legend at top/bottom
• Add test coverage for BarChart margin behavior with legend at top/bottom
• Ensure legend height is added to user's margin value rather than replacing it

Previously, when the legend was positioned at the top, user-provided margin.top values were overridden by the legend calculation. Now the user's margin takes precedence and the legend height is properly added to it.

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)?

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

No, it does not.

Testing instructions:

• Test LineChart with custom margin and legend at top:

  <LineChart
    data={sampleData}
    showLegend={true}
    legendPosition="top"
    margin={{ top: 50, right: 20, bottom: 20, left: 20 }}
  />

• Verify that the custom margin.top value (50px) is respected and the legend height is added to it
• Test BarChart with the same configuration
• Verify charts render correctly with legend at top and custom margins
• Verify charts still work with default margins when none are provided
• Verify charts work correctly with legend at bottom position
• Run the test suite: pnpm test
• All 539 tests should pass including 6 new margin-related tests

[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 WoA dev 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 (Jetpack), and enable the charts-43-legends-ensure-that-the-user-provided-margin-prop-takes branch.
• To test on Simple, run the following command on your sandbox:

bin/jetpack-downloader test jetpack charts-43-legends-ensure-that-the-user-provided-margin-prop-takes

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[github-actions]

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[Copilot]

Pull Request Overview

This PR fixes a bug where user-provided margin.top values were being overridden when legends were positioned at the top in LineChart and BarChart components. The fix ensures that custom margin values take precedence and the legend height is properly added to them rather than replacing them.

Key Changes:

• Updated margin calculation logic in both LineChart and BarChart to use margin?.top ?? defaultMargin.top pattern
• Added comprehensive test coverage (6 new tests) for margin behavior with legends at different positions

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
line-chart.tsx	Fixed margin.top calculation to respect user-provided values when legend is at top
bar-chart.tsx	Fixed margin.top calculation to respect user-provided values when legend is at top
line-chart.test.tsx	Added 3 tests covering margin behavior with legend positioning
bar-chart.test.tsx	Added 3 tests covering margin behavior with legend positioning
changelog/charts-43-legends-ensure-that-the-user-provided-margin-prop-takes	Added changelog entry documenting the fix

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[jp-launch-control]

Code Coverage Summary

This PR did not change code coverage!

That could be good or bad, depending on the situation. Everything covered before, and still is? Great! Nothing was covered before? Not so great. 🤷

Full summary · PHP report · JS report