validation: only call UpdatedBlockTip for active chainstate

This notification isn't needed for background chainstates.

`kernel::Notifications::blockTip` are also skipped.

src/validation.cpp

@@ -3263,7 +3263,7 @@ bool Chainstate::ActivateBestChain(BlockValidationState& state, std::shared_ptr<
 
             // Notify external listeners about the new tip.
             // Enqueue while holding cs_main to ensure that UpdatedBlockTip is called in the order in which blocks are connected
-            if (pindexFork != pindexNewTip) {
+            if (this == &m_chainman.ActiveChainstate() && pindexFork != pindexNewTip) {
                 // Notify ValidationInterface subscribers
                 GetMainSignals().UpdatedBlockTip(pindexNewTip, pindexFork, still_in_ibd);