Clean up power/thermal to use readJsonObject

Change-Id: I69ed29472b209e8782be63c3f0f2e8ca63dc14a4
Signed-off-by: Ed Tanous <ed@tanous.net>
diff --git a/redfish-core/lib/thermal.hpp b/redfish-core/lib/thermal.hpp
index 9d057f2..7e840d2 100644
--- a/redfish-core/lib/thermal.hpp
+++ b/redfish-core/lib/thermal.hpp
@@ -55,9 +55,10 @@
             return;
         }
 
-        std::optional<std::vector<nlohmann::json>> temperatureCollections;
-        std::optional<std::vector<nlohmann::json>> fanCollections;
-        std::unordered_map<std::string, std::vector<nlohmann::json>>
+        std::optional<std::vector<nlohmann::json::object_t>>
+            temperatureCollections;
+        std::optional<std::vector<nlohmann::json::object_t>> fanCollections;
+        std::unordered_map<std::string, std::vector<nlohmann::json::object_t>>
             allCollections;
 
         auto sensorsAsyncResp = std::make_shared<SensorsAsyncResp>(