Snapping to an axis aligned view with a 45 degree rotation would
set the view orthographic without setting it back to perspective
when orbiting the view as you would expect with auto-perspective.
Now orthographic is only set for views with rotation of 0, 90, 180, -90.
Notes:
- Partially reverts logic from cebd025e02
at the time RegionView3D.view_axis_roll had not been added,
so only setting the orthographic with one particular rotation
was a bigger limitation than it is now.
- Auto-perspective could be supported when snapping the viewport to
diagonal angles, however that's a larger project.
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