Merge dashpay#6340: fix: make 6336 compile in v21.1.x branch, using older CHECK_NONFATAL functionality

a7bbcc8 fix: make 6336 compile in v21.1.x branch, using older CHECK_NONFATAL functionality (pasta)

Pull request description:

  ## Issue being fixed or feature implemented
  Resolve build failures when 6336 is back ported

  ## What was done?
  Use older functionality of CHECK_NONFATAL

  ## How Has This Been Tested?
  built on both branches

  ## Breaking Changes

  ## Checklist:
    _Go over all the following points, and put an `x` in all the boxes that apply._
  - [ ] I have performed a self-review of my own code
  - [ ] I have commented my code, particularly in hard-to-understand areas
  - [ ] I have added or updated relevant unit/integration/functional/e2e tests
  - [ ] I have made corresponding changes to the documentation
  - [x] I have assigned this pull request to a milestone _(for repository code-owners and collaborators only)_

ACKs for top commit:
  knst:
    utACK a7bbcc8
  UdjinM6:
    utACK a7bbcc8 (dashpay#6339 compiles with this one applied on top of it)
  kwvg:
    utACK a7bbcc8

Tree-SHA512: 17b6d8223f653eaafa6ef9d1a4e8fc14ca1fe1623fbb13d23a9429e87a64c8fae3ddaf6d2d8d5a52138ab712a36949662b38a8a9cbbc5db3618ce24f565f6f2a

Author: PastaPastaPasta

src/core_write.cpp

@@ -336,7 +336,9 @@ void TxToUniv(const CTransaction& tx, const uint256& hashBlock, bool include_add
     if (calculate_fee) {
         CAmount fee = amt_total_in - amt_total_out;
         if (tx.IsPlatformTransfer()) {
-            fee = CHECK_NONFATAL(GetTxPayload<CAssetUnlockPayload>(tx))->getFee();
+            auto payload = GetTxPayload<CAssetUnlockPayload>(tx);
+            CHECK_NONFATAL(payload);
+            fee = payload->getFee();
         }
         CHECK_NONFATAL(MoneyRange(fee));
         entry.pushKV("fee", ValueFromAmount(fee));

src/rpc/blockchain.cpp

@@ -2426,7 +2426,9 @@ static RPCHelpMan getblockstats()
             CAmount txfee = tx_total_in - tx_total_out;
 
             if (tx->IsPlatformTransfer()) {
-                txfee = CHECK_NONFATAL(GetTxPayload<CAssetUnlockPayload>(*tx))->getFee();
+                auto payload = GetTxPayload<CAssetUnlockPayload>(*tx);
+                CHECK_NONFATAL(payload);
+                txfee = payload->getFee();
             }
 
             CHECK_NONFATAL(MoneyRange(txfee));

src/rpc/masternode.cpp

@@ -411,7 +411,9 @@ static RPCHelpMan masternode_payments()
                 continue;
             }
             if (tx->IsPlatformTransfer()) {
-                nBlockFees += CHECK_NONFATAL(GetTxPayload<CAssetUnlockPayload>(*tx))->getFee();
+                auto payload = GetTxPayload<CAssetUnlockPayload>(*tx);
+                CHECK_NONFATAL(payload);
+                nBlockFees += payload->getFee();
                 continue;
             }