bevy_core_pipeline: Apply #![warn(clippy::allow_attributes, clippy::allow_attributes_without_reason)] (#17137)

# 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_core_pipeline` in line with the new restrictions.

## Testing
`cargo clippy` and `cargo test --package bevy_core_pipeline` were run,
and no warnings were encountered.

crates/bevy_core_pipeline/src/auto_exposure/compensation_curve.rs

@@ -136,7 +136,10 @@ impl AutoExposureCompensationCurve {
                 let lut_inv_range = 1.0 / (lut_end - lut_begin);
 
                 // Iterate over all LUT entries whose pixel centers fall within the current segment.
-                #[allow(clippy::needless_range_loop)]
+                #[expect(
+                    clippy::needless_range_loop,
+                    reason = "This for-loop also uses `i` to calculate a value `t`."
+                )]
                 for i in lut_begin.ceil() as usize..=lut_end.floor() as usize {
                     let t = (i as f32 - lut_begin) * lut_inv_range;
                     lut[i] = previous.y.lerp(current.y, t);

crates/bevy_core_pipeline/src/lib.rs

@@ -1,5 +1,10 @@
 #![expect(missing_docs, reason = "Not all docs are written yet, see #3492.")]
 #![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",

crates/bevy_core_pipeline/src/tonemapping/mod.rs

@@ -431,8 +431,11 @@ pub fn get_lut_bind_group_layout_entries() -> [BindGroupLayoutEntryBuilder; 2] {
     ]
 }
 
-// allow(dead_code) so it doesn't complain when the tonemapping_luts feature is disabled
-#[allow(dead_code)]
+#[expect(clippy::allow_attributes, reason = "`dead_code` is not always linted.")]
+#[allow(
+    dead_code,
+    reason = "There is unused code when the `tonemapping_luts` feature is disabled."
+)]
 fn setup_tonemapping_lut_image(bytes: &[u8], image_type: ImageType) -> Image {
     let image_sampler = ImageSampler::Descriptor(bevy_image::ImageSamplerDescriptor {
         label: Some("Tonemapping LUT sampler".to_string()),