Remove nlohmann brace initialization

There's a few last places (outside of tests) where we still use
nlohmann brace initialization.  Per the transforms we've been doing,
move these to constructing the objects explicitly, using operator[],
nlohmann::object_t and nlohmann::array_t.  Theses were found by manual
inspection grepping for all uses of nlohmann::json.

This is done to reduce binary size and reduce the number of intermediate
objects being constructed.  This commit saves a trivial amount of size
(~4KB, Half a percent of total) and in addition but makes our
construction consistent.

Tested:
Redfish service validator passes.

Signed-off-by: Ed Tanous <edtanous@google.com>
Change-Id: I7478479a9fdc41b254eef325002d413c1fb411a0
diff --git a/redfish-core/lib/event_service.hpp b/redfish-core/lib/event_service.hpp
index 9c5b378..d473c8e 100644
--- a/redfish-core/lib/event_service.hpp
+++ b/redfish-core/lib/event_service.hpp
@@ -83,13 +83,16 @@
         asyncResp->res.jsonValue["RegistryPrefixes"] = supportedRegPrefixes;
         asyncResp->res.jsonValue["ResourceTypes"] = supportedResourceTypes;
 
-        nlohmann::json supportedSSEFilters = {
-            {"EventFormatType", true},        {"MessageId", true},
-            {"MetricReportDefinition", true}, {"RegistryPrefix", true},
-            {"OriginResource", false},        {"ResourceType", false}};
+        nlohmann::json::object_t supportedSSEFilters;
+        supportedSSEFilters["EventFormatType"] = true;
+        supportedSSEFilters["MessageId"] = true;
+        supportedSSEFilters["MetricReportDefinition"] = true;
+        supportedSSEFilters["RegistryPrefix"] = true;
+        supportedSSEFilters["OriginResource"] = false;
+        supportedSSEFilters["ResourceType"] = false;
 
         asyncResp->res.jsonValue["SSEFilterPropertiesSupported"] =
-            supportedSSEFilters;
+            std::move(supportedSSEFilters);
         });
 
     BMCWEB_ROUTE(app, "/redfish/v1/EventService/")