bevy_macro_utils: Apply #![warn(clippy::allow_attributes, clippy::allow_attributes_without_reason)] (#17304)

# Objective
- https://github.com/bevyengine/bevy/issues/17111

## Solution
Set the `clippy::allow_attributes` and
`clippy::allow_attributes_without_reason` lints to `warn`, and bring
`bevy_macro_utils` in line with the new restrictions.

## Testing
`cargo clippy --tests --all-features --package bevy_macro_utils` was
run, and no warnings were encountered.

crates/bevy_macro_utils/src/lib.rs

@@ -1,4 +1,9 @@
 #![forbid(unsafe_code)]
+#![warn(
+    clippy::allow_attributes,
+    clippy::allow_attributes_without_reason,
+    reason = "See #17111; To be removed once all crates are in-line with these attributes"
+)]
 #![cfg_attr(docsrs, feature(doc_auto_cfg))]
 #![doc(
     html_logo_url = "https://bevyengine.org/assets/icon.png",