Metrics Lambda is deployed as both ARM and x86

The metrics lambda is being deployed as both ARM and x86 because it's using the same action as the actual benchmark lambdas. Since this is just aggregating metrics and not being measured itself, we don't need it in both architectures. The only impact is that our metrics will be duplicated, but since the charts are taking "Avg" it shouldn't really affect the data. But this would be nice to clean up.