Fix wireframe for skinned/morphed meshes (#9734)

# Objective

- Fixes #6662 
- Wireframe crash for skinned meshes:
```
wgpu error: Validation Error

Caused by:
    In Device::create_render_pipeline
      note: label = `opaque_mesh_pipeline`
    Error matching ShaderStages(VERTEX) shader requirements against the pipeline
    Location[4] Uint32x4 interpolated as Some(Flat) with sampling None is not provided by the previous stage outputs
    Input is not provided by the earlier stage in the pipeline
```
- Wireframe crash for morphed meshes:
```
wgpu error: Validation Error

Caused by:
    In a RenderPass
      note: encoder = `<CommandBuffer-(0, 14, Metal)>`
    In a draw command, indexed:true indirect:false
      note: render pipeline = `opaque_mesh_pipeline`
    The pipeline layout, associated with the current render pipeline, contains a bind group layout at index 1 which is incompatible with the bind group layout associated with the bind group at 1
```

## Solution


- Fix the locations for skinned meshes in the wireframe shader
- Add the morph key to the wireframe specialisation key
- Morph the vertex in the wireframe shader


https://github.com/bevyengine/bevy/assets/8672791/ce0a9584-bd28-4d74-9c3f-256602e6fac5

crates/bevy_pbr/src/render/wireframe.wgsl

@@ -1,5 +1,6 @@
 #import bevy_pbr::mesh_bindings    mesh
 #import bevy_pbr::mesh_functions   get_model_matrix, mesh_position_local_to_clip
+#import bevy_pbr::morph
 
 #ifdef SKINNED
     #import bevy_pbr::skinning
@@ -9,8 +10,11 @@ struct Vertex {
     @builtin(instance_index) instance_index: u32,
     @location(0) position: vec3<f32>,
 #ifdef SKINNED
-    @location(4) joint_indexes: vec4<u32>,
-    @location(5) joint_weights: vec4<f32>,
+    @location(5) joint_indexes: vec4<u32>,
+    @location(6) joint_weights: vec4<f32>,
+#endif
+#ifdef MORPH_TARGETS
+    @builtin(vertex_index) index: u32,
 #endif
 };
 
@@ -18,8 +22,31 @@ struct VertexOutput {
     @builtin(position) clip_position: vec4<f32>,
 };
 
+
+#ifdef MORPH_TARGETS
+fn morph_vertex(vertex_in: Vertex) -> Vertex {
+    var vertex = vertex_in;
+    let weight_count = bevy_pbr::morph::layer_count();
+    for (var i: u32 = 0u; i < weight_count; i ++) {
+        let weight = bevy_pbr::morph::weight_at(i);
+        if weight == 0.0 {
+            continue;
+        }
+        vertex.position += weight * bevy_pbr::morph::morph(vertex.index, bevy_pbr::morph::position_offset, i);
+    }
+    return vertex;
+}
+#endif
+
 @vertex
-fn vertex(vertex: Vertex) -> VertexOutput {
+fn vertex(vertex_no_morph: Vertex) -> VertexOutput {
+
+#ifdef MORPH_TARGETS
+    var vertex = morph_vertex(vertex_no_morph);
+#else
+    var vertex = vertex_no_morph;
+#endif
+
 #ifdef SKINNED
     let model = bevy_pbr::skinning::skin_model(vertex.joint_indexes, vertex.joint_weights);
 #else

crates/bevy_pbr/src/wireframe.rs

@@ -130,8 +130,11 @@ fn queue_wireframes(
         let add_render_phase =
             |(entity, mesh_handle, mesh_transforms): (Entity, &Handle<Mesh>, &MeshTransforms)| {
                 if let Some(mesh) = render_meshes.get(mesh_handle) {
-                    let key = view_key
+                    let mut key = view_key
                         | MeshPipelineKey::from_primitive_topology(mesh.primitive_topology);
+                    if mesh.morph_targets.is_some() {
+                        key |= MeshPipelineKey::MORPH_TARGETS;
+                    }
                     let pipeline_id = pipelines.specialize(
                         &pipeline_cache,
                         &wireframe_pipeline,