Option to accept/discard hunk does not show when opening diffs from SCM view

[bpasero]

There is a nice way from an edit to seeing the accept/discard buttons when I click the diff icon from the editor:

But when I open a diff from the changes view, I miss that:

Ideally we get the controls in all experiences.

//cc @lszomoru

[lszomoru]

+100 on making the accept/discard hunk experience consistent.