Add padAngle to DonutChart

[envex]

What does this implement/fix?

Added padAngle to DonutChart so that all slices will render even when then min/max values are wildly different.

Does this close any currently open issues?

Resolves https://github.com/Shopify/merchant-analytics-issues/issues/511

What do the changes look like?

Before	After

Storybook link

https://6062ad4a2d14cd0021539c1b-ntboeyaprp.chromatic.com/?path=/story/polaris-viz-chromatic-charts-donutchart--tiny-slices

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%)	1.1 s (-19% 🔽)	2.3 s
polaris-viz-cjs	231.52 KB (+0.01% 🔺)	4.7 s (+0.01% 🔺)	2.2 s (+1.72% 🔺)	6.9 s
polaris-viz-esm	187.92 KB (+0.01% 🔺)	3.8 s (+0.01% 🔺)	1.5 s (+0.03% 🔺)	5.3 s
polaris-viz-css	6.05 KB (0%)	122 ms (0%)	440 ms (+5.33% 🔺)	561 ms
polaris-viz-esnext	194.7 KB (+0.01% 🔺)	3.9 s (+0.01% 🔺)	1.3 s (-18.25% 🔽)	5.2 s

[michaelnesen]

Nice looks good! 🚀