[Bug] Theme type is wrong

[uladzimir-miadzinski]

Describe the bug

It is impossible to override themes using "theme" attribute because of bug in types

Steps to reproduce the behavior

1. Install latest 6.0.2
2. Copy example from your docs https://www.npmjs.com/package/react-inspector#theme

3. 
   import { chromeLight } from 'react-inspector'

<Inspector theme={{...chromeLight, ...({ TREENODE_PADDING_LEFT: 20 })}} data={{a: 'a', b: 'b'}}/>

4. Add `table={false}` because now it is required attribute.
5. See error that theme should be of type `"string"`

### Expected behavior

Theme of type `string | Record<string, string | number> | undefined`. 

### Screenshots and/or logs

![image](https://github.com/storybookjs/react-inspector/assets/8378842/86f10de8-45b1-4e30-aa5f-6c7a1c499820)

### Environment

 - OS: Windows 10 x64
 - Node.js version: 20.10.0
 - NPM version: 10.2.3
 - Browser (if applicable): Latest Chrome

### Additional context

p.s. the same happens if we try to use `ObjectInspector`

[sethjuarez]

Any thoughts on this one? I've dug through the whole object model and can't find a way to override things properly?

[eranimo]

Seems like a huge regression?