Add supports_texture_sample_count method to Metal and Vulkan.

[huacnlee]

There need a method to check if the system supports a specific sample count.

Ref zed-industries/zed#22812 need this feature to setup sample_count.

[huacnlee]

cargo run --example particle

Tested particle example on Windows and macOS, is looks worked will.

[EriKWDev]

Nice addition!

In the particle example, the dropdown for selecting the MSAA count could perhaps use the list of supported formats? Currently hard-coded to:

for i in [1, 2, 4] {
// ...
}

[huacnlee]

You're right, I changed it.

[kvark]

Thank you!