Add load_untyped to LoadContext (#10526)

# Objective

Give us the ability to load untyped assets in AssetLoaders.

## Solution

Basically just copied the code from `load`, but used
`asset_server.load_untyped` instead internally.

## Changelog

Added `load_untyped` method to `LoadContext`

crates/bevy_asset/src/loader.rs

@@ -5,8 +5,8 @@ use crate::{
         Settings,
     },
     path::AssetPath,
-    Asset, AssetLoadError, AssetServer, AssetServerMode, Assets, Handle, UntypedAssetId,
+    Asset, AssetLoadError, AssetServer, AssetServerMode, Assets, Handle, LoadedUntypedAsset,
-    UntypedHandle,
+    UntypedAssetId, UntypedHandle,
 };
 use bevy_ecs::world::World;
 use bevy_utils::{BoxedFuture, CowArc, HashMap, HashSet};
@@ -462,6 +462,21 @@ impl<'a> LoadContext<'a> {
         handle
     }
 
+    /// Retrieves a handle for the asset at the given path and adds that path as a dependency of the asset without knowing its type.
+    pub fn load_untyped<'b>(
+        &mut self,
+        path: impl Into<AssetPath<'b>>,
+    ) -> Handle<LoadedUntypedAsset> {
+        let path = path.into().to_owned();
+        let handle = if self.should_load_dependencies {
+            self.asset_server.load_untyped(path)
+        } else {
+            self.asset_server.get_or_create_path_handle(path, None)
+        };
+        self.dependencies.insert(handle.id().untyped());
+        handle
+    }
+
     /// Loads the [`Asset`] of type `A` at the given `path` with the given [`AssetLoader::Settings`] settings `S`. This is a "deferred"
     /// load. If the settings type `S` does not match the settings expected by `A`'s asset loader, an error will be printed to the log
     /// and the asset load will fail.