wasm_wit_component: exported `imports` conflicts with generated `imports` field

## Environment
- wasm_wit_component: 0.0.1
- Dart SDK: >= 3.10.0
- OS: Ubuntu 22.04.5 LTS (x86_64)

## WIT
```
package demo:poc

world example {
  export imports: func() -> u32
}
```

## Observed
`dart analyze` fails with `duplicate_definition`