[eslint-plugin] 'Computed key cannot be resolved' when overwriting var

**The problem**

```
Computed key cannot be resolved.eslint(@stylexjs/valid-styles)
```

**How to reproduce**

```tsx
// bug.stylex.ts

import * as stylex from '@stylexjs/stylex';

const vars = {
color: 'red',
};

export const componentVars = stylex.defineVars(vars);
```

```tsx
// bug.ts

import * as stylex from '@stylexjs/stylex';

import { componentVars } from './bug.stylex';

export const styles = stylex.create({
host: {
[componentVars.color]: 'blue',
// ^^^^^^^^^^^^^^^^^^^
},
});
```