Duplicate static `from*` helper methods are produced

Given the following snippet from a JSON Schema:

```json
{
"shell": {
"anyOf": [
{
"type": "string"
},
{
"type": "string",
"enum": ["bash", "pwsh", "python", "sh", "cmd", "powershell"]
}
]
}
}
```

Will produce invalid code, where `fromString` is duplicated:

```ts
export class Shell {
public static fromString(value: string): Shell {
return new Shell(value);
}
public static fromString(value: string): Shell {
return new Shell(value);
}
private constructor(public readonly value: string | string) {
}
}
```