Removed extra output line in optimization

[leighmcculloch]

What

Removed output line in optimization saying that a file will be written.

Example

Before

$ soroban contract optimize --wasm ./out/webauthn_factory.wasm
Reading: ./out/webauthn_factory.wasm (661 bytes)
Writing to: ./out/webauthn_factory.optimized.wasm...
Optimized: ./out/webauthn_factory.optimized.wasm (586 bytes)

After

$ soroban contract optimize --wasm ./out/webauthn_factory.wasm
Reading: ./out/webauthn_factory.wasm (661 bytes)
Optimized: ./out/webauthn_factory.optimized.wasm (586 bytes)

Why

It is immediately followed with an output line that the file has been written, and the duplicate lines is unnecessary noise in the output.