Bench build should be "--hard-link"-ed by default

### Information about bug

Bench build from dashboard fails because vanilla bench build creates symlinks instead of moving the build assets to the folder they're supposed to be served from.

### Steps to Reproduce

Add the hard-link flag to the docker command if missing.

### Relevant log output / Stack trace / Full Error Message.

```shell

```

Start by locating the dashboard's Docker command for `bench build` and compare it with the requested `--hard-link` option. Reproduce the dashboard build, then verify that build assets are placed in the folder they are served from without symlinks.

Written by the indexing model from the issue text.