Fix off-by-one error on Image::get_color_at and Image::set_color_at. (#16475)

# Objective

- Fixes #16474.

## Solution

- Check that the pixel x,y,z is less than width,height,depth.
    - Classic off-by-one.

## Testing

- Added a test.

crates/bevy_image/src/image.rs

@@ -944,19 +944,19 @@ impl Image {
         let pixel_size = self.texture_descriptor.format.pixel_size();
         let pixel_offset = match self.texture_descriptor.dimension {
             TextureDimension::D3 => {
-                if coords.x > width || coords.y > height || coords.z > depth {
+                if coords.x >= width || coords.y >= height || coords.z >= depth {
                     return None;
                 }
                 coords.z * height * width + coords.y * width + coords.x
             }
             TextureDimension::D2 => {
-                if coords.x > width || coords.y > height {
+                if coords.x >= width || coords.y >= height {
                     return None;
                 }
                 coords.y * width + coords.x
             }
             TextureDimension::D1 => {
-                if coords.x > width {
+                if coords.x >= width {
                     return None;
                 }
                 coords.x
@@ -1573,4 +1573,28 @@ mod test {
         assert_eq!(UVec2::ONE, image.size());
         assert_eq!(Vec2::ONE, image.size_f32());
     }
+
+    #[test]
+    fn on_edge_pixel_is_invalid() {
+        let image = Image::new_fill(
+            Extent3d {
+                width: 5,
+                height: 10,
+                depth_or_array_layers: 1,
+            },
+            TextureDimension::D2,
+            &[0, 0, 0, 255],
+            TextureFormat::Rgba8Unorm,
+            RenderAssetUsages::MAIN_WORLD,
+        );
+        assert!(matches!(image.get_color_at(4, 9), Ok(Color::BLACK)));
+        assert!(matches!(
+            image.get_color_at(0, 10),
+            Err(TextureAccessError::OutOfBounds { x: 0, y: 10, z: 0 })
+        ));
+        assert!(matches!(
+            image.get_color_at(5, 10),
+            Err(TextureAccessError::OutOfBounds { x: 5, y: 10, z: 0 })
+        ));
+    }
 }