"extern blocks must be unsafe" for 2024 edition

[zroug]

Describe the Bug

wasm_bindgen attribute doesn't work for extern blocks in 2024 edition.

Steps to Reproduce

1. Use rustc 1.84.0-nightly and configure project to use 2024 edition.
2. Try to compile

   use wasm_bindgen::prelude::*;
   
   #[wasm_bindgen]
   extern {
       pub fn test();
   }

3. Playground link (but it can't be reproduced on the playground because it only affects the WASM target).

Expected Behavior

The example should compile.

Actual Behavior

error: extern blocks must be unsafe
 --> src/test.rs:5:9
  |
5 |     pub fn test();
  |            ^^^^

Note: Adding the unsafe keyword to the extern block doesn't help, same error.