[bug] checkUpdate doesn't return anything if no update found

[billyjacoby]

Describe the bug

When calling the checkUpdate function from the javascript API if there is not an update available the function doesn't return anything and just hangs.

Reproduction

Create a new Tauri app with updates enabled and configured and call the checkUpdate function.

An example can be found in my Browsernaut repo.

Expected behavior

If there is no update available then false is returned for UpdateResult.shouldUpdate

Platform and versions

[✔] Environment
    - OS: Mac OS 13.4.0 X64
    ✔ Xcode Command Line Tools: installed
    ✔ rustc: 1.68.2 (9eb3afe9e 2023-03-27)
    ✔ Cargo: 1.68.2 (6feb7c9cf 2023-03-26)
    ✔ rustup: 1.25.2 (17db695f1 2023-02-01)
    ✔ Rust toolchain: stable-x86_64-apple-darwin (default)
    - node: 18.16.0
    - yarn: 3.5.0
    - npm: 9.5.1

[-] Packages
    - tauri [RUST]: 1.3.0
    - tauri-build [RUST]: 1.3.0
    - wry [RUST]: 0.24.3
    - tao [RUST]: 0.16.1
    - @tauri-apps/api [NPM]: 1.3.0
    - @tauri-apps/cli [NPM]: 1.3.1

[-] App

Stack trace

No response

Additional context

No response