xtask: Check for licenses that are duplicated instead of being symlinked (#11777)

This PR updates `cargo xtask licenses` to also check for license files
that are not symlinks.

Release Notes:

- N/A

tooling/xtask/src/tasks/licenses.rs

@@ -9,15 +9,18 @@ use crate::workspace::load_workspace;
 pub struct LicensesArgs {}
 
 pub fn run_licenses(_args: LicensesArgs) -> Result<()> {
+    const LICENSE_FILES: &[&'static str] = &["LICENSE-APACHE", "LICENSE-GPL", "LICENSE-AGPL"];
+
     let workspace = load_workspace()?;
 
     for member in workspace.members {
         let crate_dir = PathBuf::from(&member);
 
-        if has_any_license_file(
-            &crate_dir,
-            &["LICENSE-APACHE", "LICENSE-GPL", "LICENSE-AGPL"],
-        ) {
+        if let Some(license_file) = first_license_file(&crate_dir, &LICENSE_FILES) {
+            if !license_file.is_symlink() {
+                println!("{} is not a symlink", license_file.display());
+            }
+
             continue;
         }
 
@@ -27,13 +30,13 @@ pub fn run_licenses(_args: LicensesArgs) -> Result<()> {
     Ok(())
 }
 
-fn has_any_license_file(path: &Path, license_files: &[&str]) -> bool {
+fn first_license_file(path: &Path, license_files: &[&str]) -> Option<PathBuf> {
     for license_file in license_files {
         let path_to_license = path.join(license_file);
         if path_to_license.exists() {
-            return true;
+            return Some(path_to_license);
         }
     }
 
-    false
+    None
 }