investigate aws-sdk-v3 client names corresponding to itty-aws services in the bundle-compare script

[kmitchener]

Check bundle size for aws-sdk-v3 clients in the README -- anything below ~50 KB is suspicious and needs investigation. It appears that the client names are incorrect. Review holistically and see if we should be extracting some larger table of data around the services that we can use in various places during code gen and in the scripts.