improves feature gating

Author: Tapanito

src/test/app/Vault_test.cpp

@@ -5024,7 +5024,7 @@ class Vault_test : public beast::unit_test::suite
                 "fixLendingProtocolV1_1 disabled",
                 all - fixLendingProtocolV1_1,
                 std::string(maxDataPayloadLength, 'A'),
-                tesSUCCESS);
+                temDISABLED);
         }
 
         {

src/xrpld/app/tx/detail/VaultDelete.cpp

@@ -19,12 +19,12 @@ VaultDelete::preflight(PreflightContext const& ctx)
         return temMALFORMED;
     }
 
-    if (ctx.rules.enabled(fixLendingProtocolV1_1))
-    {
-        // The sfData field is an optional field used to record the deletion reason.
-        if (auto const data = ctx.tx[~sfData]; data && !validDataLength(data, maxDataPayloadLength))
-            return temMALFORMED;
-    }
+    if (ctx.tx.isFieldPresent(sfData) && !ctx.rules.enabled(fixLendingProtocolV1_1))
+        return temDISABLED;
+
+    // The sfData field is an optional field used to record the deletion reason.
+    if (auto const data = ctx.tx[~sfData]; data && !validDataLength(data, maxDataPayloadLength))
+        return temMALFORMED;
 
     return tesSUCCESS;
 }