Remove useless mapRequest tracking that just effects Qt display.

I thought we had removed this a long time ago, TBH, its really
confusing feedback to users that we display whether a tx was
broadcast to immediate neighbor nodes, given that has little
indication of whether the tx propagated very far.

src/interfaces/wallet.cpp

@@ -93,7 +93,6 @@ WalletTxStatus MakeWalletTxStatus(const CWalletTx& wtx)
     result.block_height = (block ? block->nHeight : std::numeric_limits<int>::max()),
     result.blocks_to_maturity = wtx.GetBlocksToMaturity();
     result.depth_in_main_chain = wtx.GetDepthInMainChain();
-    result.request_count = wtx.GetRequestCount();
     result.time_received = wtx.nTimeReceived;
     result.lock_time = wtx.tx->nLockTime;
     result.is_final = CheckFinalTx(*wtx.tx);