fix gltf path texture usages (#22086)

# Objective

the asset usages from `GltfLoaderSettings::load_materials` are not
respected when loading path-based / non-embedded textures.

## Solution

use them

Author: robtfm

crates/bevy_gltf/src/loader/mod.rs

@@ -1137,6 +1137,7 @@ async fn load_image<'a, 'b>(
                     path: image_path,
                     is_srgb,
                     sampler_descriptor,
+                    render_asset_usages: settings.load_materials,
                 })
             }
         }
@@ -1811,6 +1812,7 @@ enum ImageOrPath {
         path: AssetPath<'static>,
         is_srgb: bool,
         sampler_descriptor: ImageSamplerDescriptor,
+        render_asset_usages: RenderAssetUsages,
     },
 }
 
@@ -1833,11 +1835,13 @@ impl ImageOrPath {
                 path,
                 is_srgb,
                 sampler_descriptor,
+                render_asset_usages,
             } => load_context
                 .loader()
                 .with_settings(move |settings: &mut ImageLoaderSettings| {
                     settings.is_srgb = is_srgb;
                     settings.sampler = ImageSampler::Descriptor(sampler_descriptor.clone());
+                    settings.asset_usage = render_asset_usages;
                 })
                 .load(path),
         };