validation: pass ChainstateRole for validationinterface calls

This allows consumers to decide how to handle events from background or
assumedvalid chainstates.

src/test/validationinterface_tests.cpp

@@ -8,6 +8,7 @@
 #include <scheduler.h>
 #include <test/util/setup_common.h>
 #include <util/check.h>
+#include <kernel/chain.h>
 #include <validationinterface.h>
 
 #include <atomic>