Change default theme to Light theme

[envex]

What does this implement/fix?

web currently uses Uplift as the current default theme, but polaris-viz defaults to the older Dark/Default theme.

We have an issue where if consumers in web don't correctly use the PolarisVizProvider the charts render the Dark/Default theme.

We're going to merge Uplift into the Light theme and change the default to Light instead of Dark/Default.

Web PR: https://github.com/Shopify/web/pull/123949

What do the changes look like?

All the charts should render with the Light theme instead of them all being Dark.

web: https://admin.web.polaris-viz-light-default.matthew-vickers.us.spin.dev/store/shop1/dashboards

Storybook link

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	61.27 KB (-0.16% 🔽)	1.3 s (-0.16% 🔽)	941 ms (-1.96% 🔽)	2.2 s
polaris-viz-cjs	216.06 KB (-0.05% 🔽)	4.4 s (-0.05% 🔽)	1.8 s (+9.04% 🔺)	6.2 s
polaris-viz-esm	176.37 KB (-0.05% 🔽)	3.6 s (-0.05% 🔽)	1.9 s (-4.73% 🔽)	5.4 s
polaris-viz-css	4.79 KB (0%)	96 ms (0%)	333 ms (-2.83% 🔽)	428 ms
polaris-viz-esnext	182.31 KB (-0.08% 🔽)	3.7 s (-0.08% 🔽)	1.6 s (-0.28% 🔽)	5.2 s

[michaelnesen]

Looks good 🫡