fix(x/tx): fallback to injected resolver for placeholder descriptors BACKPORT (#24409)

Co-authored-by: Matt Kocubinski <mkocubinski@gmail.com>

x/tx/decode/unknown.go

@@ -96,6 +96,17 @@ func doRejectUnknownFields(
 		if fieldMessage == nil {
 			continue
 		}
+		// if a message descriptor is a placeholder resolve it using the injected resolver.
+		// this can happen when a descriptor has been registered in the
+		// "google.golang.org/protobuf" resgistry but not in "github.com/cosmos/gogoproto".
+		// fixes: https://github.com/cosmos/cosmos-sdk/issues/22574
+		if fieldMessage.IsPlaceholder() {
+			gogoDesc, err := resolver.FindDescriptorByName(fieldMessage.FullName())
+			if err != nil {
+				return hasUnknownNonCriticals, fmt.Errorf("could not resolve placeholder descriptor: %v: %w", fieldMessage, err)
+			}
+			fieldMessage = gogoDesc.(protoreflect.MessageDescriptor)
+		}
 
 		// consume length prefix of nested message
 		_, o := protowire.ConsumeVarint(fieldBytes)