[v4] feat: convert icons to FCs, wrap with forwardRef

[adidahiya]

Changes proposed in this pull request:

• Convert <Icon> and auto-generated icon components in packages/icons/src/generated into function components
  • ⚠️ breaking change: Icon no longer has static constants on its public API; use IconSize from @blueprintjs/icons (or @blueprintjs/core, where it is re-exported) instead.
• Wrap these components with React.forwardRef() so that they can be more easily used as children of <ResizeSensor>

Reviewers should focus on:

• No regressions
• Is removal of Icon.SIZE_STANDARD and Icon.SIZE_LARGE constants ok?
  • Deprecation done on develop with [core] deprecate Icon, Drawer, Spinner size constant static members #4688

[blueprint-bot]

fix size constant usage, re-export in core

Previews: documentation | landing | table

[blueprint-bot]

WIP fix tess

Previews: documentation | landing | table

[adidahiya]

• Need to update based on changes committed in [core] deprecate Icon, Drawer, Spinner size constant static members #4688

[blueprint-bot]

Merge remote-tracking branch 'origin/next' into ad/v4-icon-forwardRef

Previews: documentation | landing | table

[blueprint-bot]

fix test suite

Previews: documentation | landing | table