Add new LineChartCumulative visualization

[Passanelli]

What does this implement/fix?

Initial implementation for new LineChartCumulative visualization
Address this task: https://github.com/Shopify/merchant-analytics-issues/issues/617

For this first iteration this visualization will be rendered inside HomeCards so they are not interactive at the moment.

figma link: https://www.figma.com/design/9Sm7SuRkGTNTCgonxhXnWO/Push-insights-to-home-proposal?node-id=1105-5699&p=f&t=0qHDAS5ng3x6stIA-0

What do the changes look like?

Storybook link

• checkout current branch passanelli/add_cumulative_line_chart
• run pnpm storybook
• go to Charts -> LineChartCumulative

Before merging

• Check your changes on a variety of browsers and devices.

• Update the Changelog's Unreleased section with your changes.

• Update relevant documentation, tests, and Storybook.

• Make sure you're exporting any new shared Components, Types and Utilities from the top level index file of the package

[github-actions]

size-limit report 📦

Path	Size	Loading time (3g)	Running time (snapdragon)	Total time
polaris-viz-core-cjs	61.74 KB (0%)	1.3 s (0%)	1.2 s (+19.64% 🔺)	2.5 s
polaris-viz-cjs	233.88 KB (+0.87% 🔺)	4.7 s (+0.87% 🔺)	2 s (-6.42% 🔽)	6.7 s
polaris-viz-esm	189.8 KB (+0.83% 🔺)	3.8 s (+0.83% 🔺)	1.6 s (+1.56% 🔺)	5.4 s
polaris-viz-css	6.05 KB (0%)	122 ms (0%)	269 ms (-30.24% 🔽)	390 ms
polaris-viz-esnext	196.6 KB (+0.82% 🔺)	4 s (+0.82% 🔺)	1.6 s (+7.24% 🔺)	5.5 s