[v5] [icons] feat: reduce bundle size, load paths instead of components

[adidahiya]

Fixes #2193 (comment), fixes #6159

Checklist

• Includes tests
• Update documentation

Changes proposed in this pull request:

• ⚠️ BREAK: refactor IconLoader to load icon path modules instead of generated React components
  • This changes the type and semantics of the icon loader function, which now has the signature Icons.load(name: IconName, size: IconSize)
  • If you were previously specifying a custom icon loading function, it will have to be adjusted to account for the new paths of the expected modules:

  loader: async (name, size) => {
    await import(
      /* webpackInclude: /\.js$/ */
      /* webpackMode: "eager" */
  -     `@blueprintjs/icons/lib/esm/generated/components/${name}`
  +     `@blueprintjs/icons/lib/esm/generated/${size}px/paths/${name}`
    ),
  }

• feat: reduce size of generated icon component modules by deduplicating code with a new shared component <SVGIconContainer>
• feat: new getIconPaths() function in @blueprintjs/icons which provides a less verbose API to statically load icon paths

Reviewers should focus on:

No regressions

Screenshot

[adidahiya]

[v5] [icons] feat: reduce bundle size, load paths instead of components

Build artifact links for this commit: documentation | landing | table | demo

This is an automated comment from the deploy-preview CircleCI job.

[adidahiya]

fix test

Build artifact links for this commit: documentation | landing | table | demo

This is an automated comment from the deploy-preview CircleCI job.