[CI][Bugfix] Fix failing V1 Test due to missing 'cache_salt' arg

[mgoin]

The CI for V1 Test is broken (https://buildkite.com/vllm/ci/builds/19044/steps?jid=01968804-ba26-4ab6-8efd-afd36c5ed73a#01968804-ba26-4ab6-8efd-afd36c5ed73a/209-2172) due to a forgotten EngineCoreRequest construction without required arg 'cache_salt'. Introduced by #17045

[github-actions]

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[mgoin]

@dr75 I'm curious if there is a reason for making cache_salt required rather than defaulting it to None?

[dr75]

@dr75 I'm curious if there is a reason for making cache_salt required rather than defaulting it to None?

As it is security relevant I wanted to avoid an insecure default, reducing the potential for a bug that causes a vulnerability.

[dr75]

What should I have done differently to avoid the broken test? Or was that a merge issue as I was actually looking for places where it is needed.