feat(richtext-lexical)!: lazy import React components to prevent client-only code from leaking into the server (#4290)

* chore(richtext-lexical): lazy import all React things

* chore(richtext-lexical): use useMemo for lazy-loaded React Components to prevent lag and flashes when parent component re-renders

* chore: make exportPointerFiles.ts script usable for other packages as well by hoisting it up to the workspace root and making it configurable

* chore(richtext-lexical): make sure no client-side code is imported by default from Features

* chore(richtext-lexical): remove unnecessary scss files

* chore(richtext-lexical): adjust package.json exports

* chore(richtext-*): lazy-import Field & Cell Components, move Client-only exports to /components subpath export

* chore(richtext-lexical): make sure nothing client-side is directly exported from the / subpath export anymore

* add missing imports

* chore: remove breaking changes for Slate

* LazyCellComponent & LazyFieldComponent

packages/payload/src/config/schema.ts

@@ -1,7 +1,7 @@
 import joi from 'joi'
 
 import { adminViewSchema } from './shared/adminViewSchema'
-import { livePreviewSchema } from './shared/componentSchema'
+import { componentSchema, livePreviewSchema } from './shared/componentSchema'
 
 const component = joi.alternatives().try(joi.object().unknown(), joi.func())
 
@@ -94,8 +94,10 @@ export default joi.object({
     .object()
     .required()
     .keys({
-      CellComponent: component.required(),
-      FieldComponent: component.required(),
+      CellComponent: componentSchema.optional(),
+      FieldComponent: componentSchema.optional(),
+      LazyCellComponent: joi.func().optional(),
+      LazyFieldComponent: joi.func().optional(),
       afterReadPromise: joi.func().optional(),
       outputSchema: joi.func().optional(),
       populationPromise: joi.func().optional(),