Fix transfer not-found test expectations

[JoshSEdwards]

Summary

• align ownership transfer not-found tests with the client response contract
• assert failure response details instead of expecting thrown exceptions
• keep the fix limited to the new transfer coverage added in Add missing VinylDNS API endpoints #104

Why

The transfer methods fetch the record set first and return a failure response when that lookup returns a non-2xx status. The implementation does not throw on a 404, and that matches the rest of the client API behavior.

Testing

• export JAVA_HOME=/Library/Java/JavaVirtualMachines/temurin-17.jdk/Contents/Home
• export PATH="$JAVA_HOME/bin:$PATH"
• mvn -Dlicense.skip=true -Dfmt.skip=true -Dtest=VinylDNSClientTest test

[snyk-io]

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[Sokitha-21]

Looks good