Added Line chart variant of the Chart component

[precious-onyenaucheya-ons]

What is the context of this PR?

Addressed ONSDESYS-297

This PR introduces the Line Chart variant of the Chart component, built based on the Torchbox POC and technical specifications. An example implementation of the chart is also included.

How to review this PR

1. Verify that the Line Chart component is implemented correctly and adheres to the Torchbox POC and technical specifications.
2. Check that the component is fully responsive across different screen sizes.
3. Confirm that the component has passed all required testing (backstop JS tests, snapshot tests, visual regression tests, and manual testing in the Python environment).
4. Validate that the component meets accessibility criteria.

Checklist

This needs to be completed by the person raising the PR.

• I have selected the correct Assignee
• I have linked the correct Issue

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[helenb]

Hi @precious-onyenaucheya-ons thank you for this - let's have a look through in our call this afternoon. I am also going to do some work to refine the line chart ticket tomorrow so we can get a better idea of what work is still to be done.