test(drive-abci): expect UnpaidConsensusError for single-tx purchase failures (issue #2867)

Two pre-existing NFT tests asserted PaidConsensusError + invalid_paid_count=1
for single-transition batches whose lone Purchase fails on
DocumentNotForSaleError or DocumentIncorrectPurchasePriceError.

With the v1 `flatten` / `merge_many` aggregators introduced in this PR
(PROTOCOL_VERSION_12+), an all-failed single-transition batch now
returns `data: None` instead of the legacy `Some(empty_vec)`. The
result flows down the unpaid path: `UnpaidConsensusError` and the tx
is removed from the block by prepare_proposal. Update the assertions
to reflect that.

Note that PR #3608 (separate, pending) restores Paid behavior for
these specific paths by emitting a BumpIdentityDataContractNonce
action so the user pays for the validation work — at which point
these tests will need to flip back to PaidConsensusError. For now this
PR alone produces UnpaidConsensus for these cases, which matches
v3.1-dev's current state without #3608's bump emission.

Author: shumkov

packages/rs-drive-abci/src/execution/validation/state_transition/state_transitions/batch/tests/document/nft.rs

@@ -1847,16 +1847,19 @@ mod nft_tests {
             .unwrap()
             .expect("expected to commit transaction");
 
-        assert_eq!(processing_result.invalid_paid_count(), 1);
+        // PROTOCOL_VERSION_12+ (issue #2867): the v1 `flatten` / `merge_many`
+        // aggregators return `data: None` when no per-transition input
+        // contributed, so a single-transition batch where the lone Purchase
+        // fails its price check now flows as `UnpaidConsensusError` (tx
+        // removed from block by prepare_proposal) instead of being recorded
+        // as a paid empty `BatchTransitionAction`.
+        assert_eq!(processing_result.invalid_unpaid_count(), 1);
+        assert_eq!(processing_result.invalid_paid_count(), 0);
 
         let result = processing_result.into_execution_results().remove(0);
 
-        let StateTransitionExecutionResult::PaidConsensusError {
-            error: consensus_error,
-            ..
-        } = result
-        else {
-            panic!("expected a paid consensus error");
+        let StateTransitionExecutionResult::UnpaidConsensusError(consensus_error) = result else {
+            panic!("expected an unpaid consensus error");
         };
         assert_eq!(consensus_error.to_string(), "5rJccTdtJfg6AxSKyrptWUug3PWjveEitTTLqBn9wHdk document can not be purchased for 35000000000, it's sale price is 50000000000 (in credits)");
     }
@@ -2355,16 +2358,19 @@ mod nft_tests {
             .unwrap()
             .expect("expected to commit transaction");
 
-        assert_eq!(processing_result.invalid_paid_count(), 1);
+        // PROTOCOL_VERSION_12+ (issue #2867): the v1 `flatten` / `merge_many`
+        // aggregators return `data: None` when no per-transition input
+        // contributed, so a single-transition batch where the lone Purchase
+        // hits `DocumentNotForSaleError` now flows as `UnpaidConsensusError`
+        // (tx removed from block by prepare_proposal) instead of being
+        // recorded as a paid empty `BatchTransitionAction`.
+        assert_eq!(processing_result.invalid_unpaid_count(), 1);
+        assert_eq!(processing_result.invalid_paid_count(), 0);
 
         let result = processing_result.into_execution_results().remove(0);
 
-        let StateTransitionExecutionResult::PaidConsensusError {
-            error: consensus_error,
-            ..
-        } = result
-        else {
-            panic!("expected a paid consensus error");
+        let StateTransitionExecutionResult::UnpaidConsensusError(consensus_error) = result else {
+            panic!("expected an unpaid consensus error");
         };
         assert_eq!(
             consensus_error.to_string(),