Update to wgpu 29 (#7990)

* [x] I have followed the instructions in the PR template

This updates wgpu to v29 across the egui crate stack.

There a a few API changes due to the requirement to provide a display
handle up front to properly support GLES on linux. I have done my best
to make the api changes as reasonable as possible, but I don't have all
the greater project context, so lmk if things should be done a bit
differently.

I've also updated glow to 0.17 to make cargo deny happy, there are no
source changes. I'm not sure how you want to land these.

---------

Co-authored-by: lucasmerlin <hi@lucasmerlin.me>

crates/egui_demo_app/src/apps/custom3d_wgpu.rs

@@ -40,7 +40,7 @@ impl Custom3d {
 
         let pipeline_layout = device.create_pipeline_layout(&wgpu::PipelineLayoutDescriptor {
             label: Some("custom3d"),
-            bind_group_layouts: &[&bind_group_layout],
+            bind_group_layouts: &[Some(&bind_group_layout)],
             immediate_size: 0,
         });