Unable to use `binaries` option to sign additional binaries

### Preflight Checklist

* [x] I have read the [contribution documentation](https://github.com/electron/packager/blob/main/CONTRIBUTING.md) for this project.
* [x] I agree to follow the [code of conduct](https://github.com/electron/electron/blob/main/CODE_OF_CONDUCT.md) that this project follows, as appropriate.
* [x] I have searched the issue tracker for a bug that matches the one I want to file, without success.

### Issue Details

* **Electron Packager Version:**
* Not relevant
* **Electron Version:**
* Not relevant
* **Operating System:**
* Not relevant
* **Last Known Working Electron Packager version:**:
* Not relevant

### Expected Behavior
I should be able to use `binaries` in `osxSign` to sign additional binaries.

### Actual Behavior
The TypeScript definition explicitly removes the `binaries` key using `Omit` which results in this error:
```
forge.config.ts:15:7 - error TS2322: Type '{ binaries: string[]; optionsForFile: () => { entitlements: string; }; }' is not assignable to type 'true | OsxSignOptions'.
Object literal may only specify known properties, and 'binaries' does not exist in type 'OsxSignOptions'.
```

### To Reproduce
```typescript
const config: ForgeConfig = {
...
packagerConfig: {
osxSign: {
binaries: ["./path/to/extra/binary"],
},
},
};
```

### Additional Information
`binaries` has been omitted since the `OsxSignOptions` type was introduced in a2a3ae559d402a0ce36a00cd0e9ceab6bcaba2db

Inspect the TypeScript definition for OsxSignOptions and the change introduced in commit a2a3ae559d402a0ce36a00cd0e9ceab6bcaba2db. Confirm that the binaries option from the documented osxSign configuration is accepted, then verify the provided ForgeConfig example type-checks.

Written by the indexing model from the issue text.