Windows: Enable clippy deny warnings (#9920)

~Waiting #9918~

Release Notes:

- N/A

tooling/xtask/src/main.rs

@@ -59,9 +59,6 @@ fn run_clippy(args: ClippyArgs) -> Result<()> {
     clippy_command.arg("--");
 
     // Deny all warnings.
-    // We don't do this yet on Windows, as it still has some warnings present.
-    // todo(windows)
-    #[cfg(not(target_os = "windows"))]
     clippy_command.args(["--deny", "warnings"]);
 
     eprintln!(