Chart Library: add bar chart component tests + improve data validation

[annacmc]

Proposed changes:

• This PR adds new edge case tests to the bar chart component
• It also resolves any discovered issues causing tests to fail
• It adds data validation to the bar chart

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:

• Run tests for the charts package:

cd projects/js-packages/charts
pnpm test

Verify that tests run successfully and pass.

In your Jetpack local env, navigate to the Storybook development environment:

pnpm i
cd projects/js-packages/storybook
pnpm run storybook:dev

Find JS Packages/Charts/Bar Chart in the sidebar then navigate down to Error States to check the possible error states

[github-actions]

Thank you for your PR!

When contributing to Jetpack, we have a few suggestions that can help us test and review your patch:

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• ✅ Add a "[Status]" label (In Progress, Needs Team Review, ...).
  
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• ✅ Add testing instructions.
  
• ✅ Specify whether this PR includes any changes to data or privacy.
  
• ✅ Add changelog entries to affected projects
  

This comment will be updated as you work on your PR and make changes. If you think that some of those checks are not needed for your PR, please explain why you think so. Thanks for cooperation 🤖

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The e2e test report can be found here. Please note that it can take a few minutes after the e2e tests checks are complete for the report to be available.

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Follow this PR Review Process:

1. Ensure all required checks appearing at the bottom of this PR are passing.
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     • Example: Updating a team-specific component or a small change to a shared library.
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