A DESCRIPTION OF THE PROBLEM :
The command reply of multiple commands erroneously (?) contains `@HostUserDetails{...}`, for example https://github.com/openjdk/jdk/pull/4382#issuecomment-901430117

The issue appears to be that some commands print '@' followed by the `HostUser`. At least for pull request commands this seems to be redundant because PullRequestCommandWorkItem.processCommand already includes that.

For commit commands the situation is slightly different because CommitCommandWorkItem.processCommand is apparently not adding the prefix `@username`.

It might therefore be good to:
(- Adjust CommitCommandWorkItem.processCommand to always print `@username ` as prefix similar to PullRequestCommandWorkItem)
- Remove all `@username` printing in pull request (and commit) command implementations