No functional changes.
Merge the modal callbacks of the `VIEW3D_OT_move`, `VIEW3D_OT_rotate`
and `VIEW3D_OT_zoom` operators into a single simplified
`view3d_navigate_modal_fn` callback.
Deduplicate code for initialization, also the code for finalization and
the code to get the `event_code`.
Improve support for operation switching by the existing (but unused)
modal keymap items `VIEWROT_MODAL_SWITCH_ZOOM`,
`VIEWROT_MODAL_SWITCH_MOVE` and
`VIEWROT_MODAL_SWITCH_ROTATE`.
Pull Request: https://projects.blender.org/blender/blender/pulls/106279
67203c0ec8