Added reporting of VK_KHR_external_memory_fd vulkan extension as feature

[SupaMaggie70Incorporated]

Connections
Builds on #7824 currently, but this requirement could probably be dropped if necessary.

Description
Previously, in order to check for support of VK_KHR_external_memory_fd vulkan extension, one had to use as_hal and check the enabled extensions. However, VK_KHR_external_memory_win32 already reported this as a feature(even though both extensions are always enabled anyway). This PR brings that to VK_KHR_external_memory_fd.

Testing
No testing, very minimal changes

Squash or Rebase?
Both should be fine, as there is only one commit at the moment.

Checklist

• Run cargo fmt.
• Run taplo format.
• Run cargo clippy --tests. If applicable, add:
  • --target wasm32-unknown-unknown
• Run cargo xtask test to run tests.
• If this contains user-facing changes, add a CHANGELOG.md entry.