refactor: reduce calls for `load_config_file` in CLI

> I wonder if we can instantiate the `CliConfig` within the function to avoid passing it from `main()` essentially. But maybe this is better to avoid loading the file many times (maybe it could be within a once cell?). There are other occurrences of this as well.

_Originally posted by @igamigo in https://github.com/0xPolygonMiden/miden-client/pull/840#discussion_r2047501343_