In the animation transform code, `T_AUTOMERGE` was used
to indicate that the duplicated keys need to be merged.
In perparation of #111051, this no longer makes much sense because
in grease pencil we cannot have two keys in the same channel at the same
frame.
This PR replaces the `T_AUTOMERGE` flag in the animation code to
`T_DUPLICATED_KEYS` to indicate that the transform is being called
with duplicated keyframes.
Pull Request: https://projects.blender.org/blender/blender/pulls/111268
In the 3D View, after navigating, the initial cursor position was
updated based on the relative position of the cursor in 3D space.
Now the initial relative position is maintained but moved closer to or
further from the 2d center based on zoom.
