fix(api): return proper json objects (#3544)

cmake/dependencies/nlohmann_json.cmake

@@ -0,0 +1,18 @@
+#
+# Loads the nlohmann_json library giving the priority to the system package first, with a fallback to FetchContent.
+#
+include_guard(GLOBAL)
+
+find_package(nlohmann_json 3.11 QUIET GLOBAL)
+if(NOT nlohmann_json_FOUND)
+    message(STATUS "nlohmann_json v3.11.x package not found in the system. Falling back to FetchContent.")
+    include(FetchContent)
+
+    FetchContent_Declare(
+            json
+            URL      https://github.com/nlohmann/json/releases/download/v3.11.3/json.tar.xz
+            URL_HASH MD5=c23a33f04786d85c29fda8d16b5f0efd
+            DOWNLOAD_EXTRACT_TIMESTAMP
+    )
+    FetchContent_MakeAvailable(json)
+endif()