Replace #[allow attributes with expect (#7796)

We do have `clippy::allow_attributes` turned on, but it doesn't seem to
work properly

xtask/src/main.rs

@@ -1,7 +1,6 @@
 //! Helper crate for running scripts within the `egui` repo
 
-#![allow(clippy::print_stdout)]
-#![allow(clippy::print_stderr)]
+#![expect(clippy::print_stderr, clippy::print_stdout)]
 #![allow(clippy::exit)]
 
 mod deny;