Keep mouse inside 3D viewport rotation widget

Hide and keep the mouse in place when the user oribts the scene via the 3D
rotation widget.

(cherry picked from commit 051f02a3a096f46f332b2cb8b7849b12b9c80c41)

editor/plugins/spatial_editor_plugin.cpp

@@ -195,12 +195,20 @@ void ViewportRotationControl::_gui_input(Ref<InputEvent> p_event) {
 				_update_focus();
 			}
 			orbiting = false;
+			if (Input::get_singleton()->get_mouse_mode() == Input::MOUSE_MODE_CAPTURED) {
+				Input::get_singleton()->set_mouse_mode(Input::MOUSE_MODE_VISIBLE);
+				Input::get_singleton()->warp_mouse_position(orbiting_mouse_start);
+			}
 		}
 	}
 
 	const Ref<InputEventMouseMotion> mm = p_event;
 	if (mm.is_valid()) {
 		if (orbiting) {
+			if (Input::get_singleton()->get_mouse_mode() == Input::MOUSE_MODE_VISIBLE) {
+				Input::get_singleton()->set_mouse_mode(Input::MOUSE_MODE_CAPTURED);
+				orbiting_mouse_start = mm->get_global_position();
+			}
 			viewport->_nav_orbit(mm, viewport->_get_warped_mouse_motion(mm));
 			focused_axis = -1;
 		} else {
@@ -2182,14 +2190,14 @@ void SpatialEditorViewport::set_freelook_active(bool active_now) {
 		}
 
 		// Hide mouse like in an FPS (warping doesn't work)
-		OS::get_singleton()->set_mouse_mode(OS::MOUSE_MODE_CAPTURED);
+		Input::get_singleton()->set_mouse_mode(Input::MOUSE_MODE_CAPTURED);
 
 	} else if (freelook_active && !active_now) {
 		// Sync camera cursor to cursor to "cut" interpolation jumps due to changing referential
 		cursor = camera_cursor;
 
 		// Restore mouse
-		OS::get_singleton()->set_mouse_mode(OS::MOUSE_MODE_VISIBLE);
+		Input::get_singleton()->set_mouse_mode(Input::MOUSE_MODE_VISIBLE);
 	}
 
 	freelook_active = active_now;

editor/plugins/spatial_editor_plugin.h

@@ -158,6 +158,7 @@ class ViewportRotationControl : public Control {
 	SpatialEditorViewport *viewport = nullptr;
 	Vector<Color> axis_colors;
 	Vector<int> axis_menu_options;
+	Vector2i orbiting_mouse_start;
 	bool orbiting = false;
 	int focused_axis = -2;