[all components] Decide on a common generic `value` type

Current situation:

value: any
- Select
- Menu Radio
- Menu Radio Group
- Toggle Group
- Tabs

value: unknown
- Field (in `validate` callback)
- Radio
- Radio Group

value: string
- Toggle Group
- Select.Value (in `children` render function)

***

My preferences/suggestions:
- We can't use `unknown` because it comes with a difficult DX
- `any` is OK but might be a footgun with non-primitive values causing unexpected rerenders due to different references. I could go either way though as it's more powerful too.
- Any potential issues with non-primitive values in forms?
- Toggle needs to align with whatever everything else is using
- Select.Value needs to use the actual `value` type for the `children` render function

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