deps(demo): upgrade to next@11

[williaster]

🏠 Internal

Before it was reverted, #1578 broke the nextjs site due to the resulting d3-* ESM modules with the error

Error [ERR_REQUIRE_ESM]: require() of ES Module /Users/christopher-williams/dev/visx/packages/visx-demo/node_modules/@visx/scale/node_modules/d3-scale/src/index.js from /Users/christopher-williams/dev/visx/packages/visx-demo/node_modules/@visx/scale/lib/scales/band.js not supported.

This PR

• updates the demo site from next@9.5.4 to next@^11 and turns on its experimental support for esm modules
  • no breaking changes for 9=>10
  • no breaking changes for us for 10=>11 because we're on react@18, but some SSR mismatch errors surfaced and I had to refactor some of our next-config + happo config which references next's webpack configuration.
• adds next-transpile-modules with config for the problematic d3-* packages
  • when trying different combinations I found this was still necessary
• fixed a @visx/visx version in visx-demo
• updated the tsconfig for visx-demo which was trying to extend a base root config which wasn't working great

verified that the site builds locally when rebased on #1578

[williaster]

this was not the latest, which meant a copy of all @visx/* packages were in a local node_modules which would hide some errors (e.g., because they were the non-ESM versions)