Dev: fix local ref leak

Author: andriydruk

compiler/src/main/java/com/readdle/codegen/SwiftCallbackFuncDescriptor.java

@@ -240,6 +240,9 @@ void generateCode(SwiftWriter swiftWriter, String javaFullName, String swiftType
         }
 
         if (returnSwiftType != null) {
+            swiftWriter.emitStatement("defer {");
+            swiftWriter.emitStatement("JNI.DeleteLocalRef(result)");
+            swiftWriter.emitStatement("}");
             swiftWriter.emitStatement("do {");
             swiftWriter.emitStatement(String.format("return try %s.from(javaObject: result)", returnSwiftType.swiftConstructorType));
             swiftWriter.emitStatement("}");