Increase file collapsing threshold when vieweing diffs file-by-file
## Description
When I'm reviewing a MR file-by-file, I'd expect to see the **whole** file like I do in my IDE :smile:
| In GitLab file-by-file | In IDE |
|----------|-------|
|  |  |
<small>Taken from this MR https://gitlab.com/gitlab-org/gitlab/-/merge_requests/42443</small>
In this example :point_up:, I don't know if we are adding a `computed` or a `method`, but when I review locally all the context is right there.
## Proposal
Let's smartly adjust the threshold of collapsing file content when reviewing file-by-file.
issue