docker-outside-of-docker: Fix moby edge case ; gid 999

> As part of the tests, I figured out an issue when using moby. It seems that the group which moby creates hasn't the gid of 999 which is the default docker gid. I added a fix for such cases as well.

The commented out code (in this PR) was added in https://github.com/devcontainers/features/pull/443 which was merged an hour ago.
The issue with moby existed even before it, in order to avoid failures for folks, we can comment this bit for now.

I'll create a followup PR to fix that edge case.

_Originally posted by @samruddhikhandale in https://github.com/devcontainers/features/pull/515#pullrequestreview-1373542490_