[docker] Use debian-slim image in client
[docker] Use debian-slim image in client

Use the smaller `-slim` image for the final client image.

Test Plan: Built and ran it

Closes: #4298
Approved by: rustielin

libra/libra,libra/libra,aptos-labs/aptos-core,aptos-labs/aptos-core,aptos-labs/aptos-core,aptos-labs/aptos-core,libra/libra,aptos-labs/aptos-core,libra/libra,libra/libra,aptos-labs/aptos-core,aptos-labs/aptos-core