fix: Correct TypeScript overload signatures in FetchMock.route()

[MatrixNeoKozak]

The route method in FetchMock.ts has overloaded signatures that accept either a single UserRouteConfig/RouteConfigWrapper argument or three arguments (matcher, response, options). The third parameter options is typed as UserRouteConfig | RouteConfigWrapper | string, which matches the provided argument types. However, the implementation uses @ts-expect-error comments to suppress TypeScript errors when calling this.route(...) from shorthand methods. This change removes the @ts-expect-error comments and adjusts the overloaded implementation signature to be more precise, ensuring that TypeScript can correctly type-check the internal calls. The fix aligns the implementation with the declared overloads and improves type safety without altering runtime behavior.