validation: Stricter assumeutxo error handling in InvalidateCoinsDBOnDisk

Currently InvalidateCoinsDBOnDisk is calling AbortNode without an error to the
caller if it fails. Change it to return just return util::Result, and update
the caller to handle the error itself.

This causes the secondary error to be shown below the main error instead of the
other way around.

src/validation.h

@@ -31,6 +31,7 @@
 #include <util/check.h>
 #include <util/fs.h>
 #include <util/hasher.h>
+#include <util/result.h>
 #include <util/translation.h>
 #include <versionbits.h>
 
@@ -810,7 +811,7 @@ private:
      * In case of an invalid snapshot, rename the coins leveldb directory so
      * that it can be examined for issue diagnosis.
      */
-    void InvalidateCoinsDBOnDisk() EXCLUSIVE_LOCKS_REQUIRED(::cs_main);
+    [[nodiscard]] util::Result<void> InvalidateCoinsDBOnDisk() EXCLUSIVE_LOCKS_REQUIRED(::cs_main);
 
     friend ChainstateManager;
 };