wallet: remove post-migration signals connection

The wallet is isolated during migration and reloaded at the end
of the process. There is no benefit on connecting the signals
few lines before unloading the wallet.

src/wallet/wallet.cpp

@@ -4275,10 +4275,6 @@ bool CWallet::ApplyMigrationData(MigrationData& data, bilingual_str& error)
     }
     local_wallet_batch.TxnCommit();
 
-    // Connect the SPKM signals
-    ConnectScriptPubKeyManNotifiers();
-    NotifyCanGetAddressesChanged();
-
     WalletLogPrintf("Wallet migration complete.\n");
 
     return true;