Fix: resolve error Cannot set properties of undefined when using signedQuery=true

[frtelg]

See issue https://github.com/jamesmbourne/aws4-axios/issues/1763.

Haven't been able to reproduce the issue the tests in this project but I managed to test the fix in the node_module of my own project.

You can however reproduce it by using the axios.get method instead of axios.request (but this is not supported in the current test setup):

Will fail:

        await this.axios.get(url, {
            ...config,
           // params property is omitted here
        });

Will succeed:

        await this.axios.get(url, {
            ...config,
            params: {
                ...config?.params,
            },
        });