fix: do not crash server if specified ADDRESS_HEADER is missing from a request

[Conduitry]

This fixes #10284 by moving the check for the presence of the header specified in ADDRESS_HEADER inside the getClientAddress function. The old behavior is that non-prerendered requests without the appropriate header will instantly crash the server. The new behavior is that getClientAddress() will throw an exception, like with the other checks.

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Latest commit: 94b03c1

The changes in this PR will be included in the next version bump.

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Name	Type
@sveltejs/adapter-node	Patch

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[bitdom8]

Hi, my server doesn't start now with old code on myserver.service: @Conduitry

ExecStart=sudo node -r dotenv/config build
WorkingDirectory=/usr/local/lsws/nodes/mynode/