Fix crash on command buffer drop

[Wumpf]

Checklist

• Run cargo clippy.
• Run RUSTFLAGS=--cfg=web_sys_unstable_apis cargo clippy --target wasm32-unknown-unknown if applicable.
• Add change to CHANGELOG.md. See simple instructions inside file.

Connections

Fixes #3724

Description

Oversight in: #3657
Passed the wrong object was passed for data to command_buffer_drop, causing type conversion assertion to fail at runtime 😱

Testing

Add minimal repro

let encoder = device.create_command_encoder(&wgpu::CommandEncoderDescriptor { label: None });
drop(encoder.finish());

to hello triangle. Before: thread 'main' panicked at 'assertion failed: data.is::<T>()', wgpu/src/context.rs:1045:5

[Wumpf]

@emilk I agree with the two comments, but I intentionally sticked with the pattern of the other drop implementations in this file to make it less confusing. If there is no data object but an id we are in an invalid state and should not continue either, so we need to handle this error in some way.
The actual issue here is that there’s two option fields that are in sync which is already pretty bad. But since this kind of check only id + unwrap is done in other places as well I decided to stick with it.

[cwfitzgerald]

Thanks!