Set OTEL_METRICS_EXPORTER=none as default in Lambda (#239)

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*Description of changes:*


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Author: jj22ee

lambda-layer/packages/layer/scripts/otel-instrument

@@ -76,9 +76,9 @@ if [ -z "${OTEL_AWS_APPLICATION_SIGNALS_ENABLED}" ]; then
     export OTEL_AWS_APPLICATION_SIGNALS_ENABLED="true";
 fi
 
-# - Enable emf exporter by default
+# - Disable otel metrics export by default
 if [ -z "${OTEL_METRICS_EXPORTER}" ]; then
-    export OTEL_METRICS_EXPORTER="awsemf";
+    export OTEL_METRICS_EXPORTER="none";
 fi
 
 # - Disable logs exporter by default