fix: check docs web test license headers (#4474)

Remove scaffold that accidentally caused the post-merge Rust
license-header check to fail. Include `docs/web-tests/**` in the PR
workflow paths so future docs test changes run the license checks before
merge.

Validation: `cargo fmt --all`; `git diff --check`;
license-header-checker v1.5.0 using all four workflow commands on a
clean checkout; Cargo metadata confirms all six Rust example targets
remain unchanged.

.github/workflows/license-header-check.yml

@@ -9,6 +9,7 @@ on:
       - python/**
       - nodejs/**
       - java/**
+      - docs/web-tests/**
       - .github/workflows/license-header-check.yml
 
 permissions:

docs/web-tests/rs/src/main.rs

@@ -1,3 +0,0 @@
-fn main() {
-    println!("Hello, world!");
-}