Merge bitcoin/bitcoin#28890: rpc: Remove deprecated -rpcserialversion

fa46cc22bc Remove deprecated -rpcserialversion (MarcoFalke)

Pull request description:

  The flag is problematic for many reasons:

  * It is deprecated
  * It is a global flag, requiring a restart to change, as opposed to a flag that can be set on each RPC invocation
  * It may be hidden in config files by accident, hard to debug, causing LND crashes and bugs, see https://github.com/bitcoin/bitcoin/issues/28730#issuecomment-1780940868
  * It makes performance improvements harder to implement: https://github.com/bitcoin/bitcoin/pull/17529#issuecomment-556082818

  Fix all issues by removing it.

  If there is a use-case, likely a per-RPC flag can be added, if needed.

ACKs for top commit:
  ajtowns:
    crACK fa46cc22bc
  TheCharlatan:
    lgtm ACK fa46cc22bc

Tree-SHA512: 96ba1c60356ce93954fe5c2a59045771c6d1516ad0d9dc436ef1800a1f1b0153f0d5fb78ca99d53ad54ba25fbce36962bdf1d4325aceedfc8154a61347a6a915

src/rpc/rawtransaction.cpp

@@ -62,7 +62,7 @@ static void TxToJSON(const CTransaction& tx, const uint256 hashBlock, UniValue&
     // Blockchain contextual information (confirmations and blocktime) is not
     // available to code in bitcoin-common, so we query them here and push the
     // data into the returned UniValue.
-    TxToUniv(tx, /*block_hash=*/uint256(), entry, /*include_hex=*/true, RPCSerializationWithoutWitness(), txundo, verbosity);
+    TxToUniv(tx, /*block_hash=*/uint256(), entry, /*include_hex=*/true, txundo, verbosity);
 
     if (!hashBlock.IsNull()) {
         LOCK(cs_main);
@@ -383,7 +383,7 @@ static RPCHelpMan getrawtransaction()
     }
 
     if (verbosity <= 0) {
-        return EncodeHexTx(*tx, /*without_witness=*/RPCSerializationWithoutWitness());
+        return EncodeHexTx(*tx);
     }
 
     UniValue result(UniValue::VOBJ);