Merge #17250: Avoid unused call to GuessVerificationProgress in NotifyHeaderTip

fa398091b7 Avoid unused call to GuessVerificationProgress in NotifyHeaderTip (MarcoFalke)

Pull request description:

  `GuessVerificationProgress` for a header (not a block) is always 0 because the number of txs in the block can not be determined from the header alone. Anyway, this result was never used, so we can optimize this call by hardcoding 0.

  This is the next commit in a series of changes toward removing nChainTx (see #14863, #13875)

ACKs for top commit:
  promag:
    Code review ACK fa398091b7, missed that.
  laanwj:
    ACK fa398091b7

Tree-SHA512: 11016f8dbb1af1cf75241948d1ad35eac0c79d1311cd0db8c6ec806df2a9e3dc5f998dbd66ccbad5d84564e6cec7fe21ce7a2a13c2b34c746e2d3b31aa1db53a

src/interfaces/node.cpp

@@ -312,7 +312,7 @@ public:
         return MakeHandler(
             ::uiInterface.NotifyHeaderTip_connect([fn](bool initial_download, const CBlockIndex* block) {
                 fn(initial_download, block->nHeight, block->GetBlockTime(),
-                    GuessVerificationProgress(Params().TxData(), block));
+                    /* verification progress is unused when a header was received */ 0);
             }));
     }
     InitInterfaces m_interfaces;