The camera frame (used for selection) was drawn outside the near
clipping plane in those cases.
This has been an issue before as seen in the following commits:
- rB6e7e6832e87
- rB33d322873e6
- rB4f9451c0442
Remaining issue was that the code which ensure the frame isn't behind
the near clipping plane was not taking into account the camera could be
scaled (in Z).
A caller of `BKE_camera_view_frame_ex` (namely
`OVERLAY_camera_cache_populate`) applies scale (also on the depth) which
does not play well with the way `BKE_camera_view_frame_ex` did it.
Now take Z scale into account.
Ref D15178
33fc230ba2