Should we remove extra checkout steps in diff actions?

[DaughterOfMars]

Description

In the github diff actions (.github/actions/diffs/action.yml and .github/actions/turnbo-diffs/action.yml) there are steps to checkout the repo. However, these are probably unnecessary as it is a requirement for the caller to have already checked out the repo in order to call these actions, as the action files will be unavailable otherwise. This means that we are checking out three times in the hierarchy's diff job.

This does protect against the situation where the caller checks out only, for instance, the .github directory. However, that is a non-issue in my opinion as there are no instances where we do this or have any reason to.