[bug] the asset protocol should respect HEAD method and not return body

[chrox]

Describe the bug

In the HTTP standard, a HEAD request is similar to a GET request but does not return a message body in the response.

The server sends back a 200 OK response comprised only of headers. The response is effectively metadata that describes the resource instead of the resource itself.

In the current implementation of the asset protocol, the response body includes the entire file content regardless of whether a HEAD method is used, which can result in unnecessary memory consumption in certain cases.

let buf = if let Some(b) = read_bytes {
      b
    } else {
      crate::async_runtime::safe_block_on(async move {
        let mut local_buf = Vec::with_capacity(len as usize);
        file.read_to_end(&mut local_buf).await?;
        Ok::<Vec<u8>, anyhow::Error>(local_buf)
      })?
    };
    resp = resp.header(CONTENT_LENGTH, len);
    resp.body(buf.into())

The screenshot shows the entire file content is downloaded which is not intended for the HEAD request.

Reproduction

No response

Expected behavior

It should not return the file content in the response body with HEAD request.

Full tauri info output

[✔] Environment
    - OS: Mac OS 14.3.1 arm64 (X64)
    ✔ Xcode Command Line Tools: installed
    ✔ rustc: 1.81.0 (eeb90cda1 2024-09-04)
    ✔ cargo: 1.81.0 (2dbb1af80 2024-08-20)
    ✔ rustup: 1.27.1 (54dd3d00f 2024-04-24)
    ✔ Rust toolchain: stable-aarch64-apple-darwin (default)
    - node: 22.5.1
    - pnpm: 9.12.0
    - yarn: 1.22.22
    - npm: 10.8.2

[-] Packages
    - tauri 🦀: 2.0.2
    - tauri-build 🦀: 2.0.1
    - wry 🦀: 0.44.1
    - tao 🦀: 0.30.3
    - @tauri-apps/api : 2.0.2
    - @tauri-apps/cli : 2.0.2

[-] Plugins
    - tauri-plugin-log 🦀: 2.0.1
    - @tauri-apps/plugin-log : 2.0.0
    - tauri-plugin-http 🦀: 2.0.1
    - @tauri-apps/plugin-http : 2.0.0
    - tauri-plugin-dialog 🦀: 2.0.1
    - @tauri-apps/plugin-dialog : 2.0.0
    - tauri-plugin-os 🦀: 2.0.1
    - @tauri-apps/plugin-os : 2.0.0
    - tauri-plugin-fs 🦀: 2.0.1
    - @tauri-apps/plugin-fs : 2.0.0

[-] App
    - build-type: bundle
    - CSP: default-src 'self' ipc: http://ipc.localhost; img-src 'self' data: asset: http://asset.localhost
    - frontendDist: ../out
    - devUrl: http://localhost:3000/
    - framework: React (Next.js)
    - bundler: Webpack

Stack trace

No response

Additional context

No response