[Rust Server] Reinstate tests

[richardwhiuk]

This reverts #8440 and updates swagger-rs to fix the tests - I'm surprised this wasn't picked up by CI automatically.

Rust Server Technical Committee

@frol @farcaller @paladinzh

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[richardwhiuk]

FYI @wing328 as you did the original reversion

[wing328]

@richardwhiuk thanks for the PR. Let me check the result later today.