fix additional iwyu warnings

Author: ethandmd

sdk/include/opentelemetry/sdk/metrics/aggregation/aggregation.h

@@ -3,8 +3,8 @@
 
 #pragma once
 
+#include <stdint.h>
 #include <memory>
-
 #include "opentelemetry/sdk/metrics/data/metric_data.h"
 #include "opentelemetry/version.h"
 

sdk/test/metrics/aggregation_test.cc

@@ -7,7 +7,6 @@
 #include <limits>
 #include <string>
 #include <vector>
-#include "opentelemetry/nostd/shared_ptr.h"
 #include "opentelemetry/nostd/variant.h"
 #include "opentelemetry/sdk/metrics/aggregation/aggregation_config.h"
 #include "opentelemetry/sdk/metrics/aggregation/base2_exponential_histogram_aggregation.h"