Blender Git Loki

3DView: ability to cancel out of viewport roll

This adds the ability to cancel out of the roll using ESC or RMB
(which is not common for viewops -- but makes sense in the case of roll
I think). This resets the view as well as potential locked cameras to
the original orientations (but does not remove potential autokeys --
which no transform does on cancel btw.)

Maniphest Tasks: T89883

Differential Revision: https://developer.blender.org/D12582