Snippet repo: Remove safe navigators and return early
The following discussion from !205897 should be addressed:
- [ ] @jwoodwardgl started a [discussion](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/205897#note_2781134159): (+1 comment)
> **nitpick(non-blocking)** you've already verified that snippet exists so the extra safe navigator is unnecessary
>
> ```suggestion:-1+0
> self.organization = snippet.organization if snippet&.organization_id.present?
> self.project = snippet.project if snippet&.project_id.present?
> ```
>
> In fact, we can actually just return early if there's no snippet and remove all safe navigators
>
> ```suggestion:-3+0
> return if compact_sharding_keys.size == 1 || snippet.nil?
>
> self.organization = snippet.organization if snippet.organization_id.present?
> self.project = snippet.project if snippet.project_id.present?
> ```
issue