Removes `propsForNextShape` and replaces it with the new styles API.
Changes in here:
- New custom style example
- `setProp` is now `setStyle` and takes a `StyleProp` instead of a
string
- `Editor.props` and `Editor.opacity` are now `Editor.sharedStyles` and
`Editor.sharedOpacity`
- They return an object that flags mixed vs shared types instead of
using null to signal mixed types
- `Editor.styles` returns a `SharedStyleMap` - keyed on `StyleProp`
instead of `string`
- `StateNode.shapeType` is now the shape util rather than just a string.
This lets us pull the styles from the shape type directly.
- `color` is no longer a core part of the editor set on the shape
parent. Individual child shapes have to use color directly.
- `propsForNextShape` is now `stylesForNextShape`
- `InstanceRecordType` is created at runtime in the same way
`ShapeRecordType` is. This is so it can pull style validators out of
shape defs for `stylesForNextShape`
- Shape type are now defined by their props rather than having separate
validators & type defs
### Change Type
- [x] `major` — Breaking change
### Test Plan
1. Big time regression testing around styles!
2. Check UI works as intended for all shape/style/tool combos
- [x] Unit Tests
- [ ] End to end tests
### Release Notes
-
---------
Co-authored-by: Steve Ruiz <steveruizok@gmail.com>