fix(api): use encoder position instead of homing gantry when placing …

…plate reader lid. (#16781)

- The plate reader lid hits the Flex side window when the gantry homes while the gripper holds the lid, don't do that! :)
- Instead, let's update the gantry position from the encoders, so we don't have to home at all.

api/src/opentrons/protocol_engine/commands/unsafe/unsafe_place_labware.py

@@ -129,9 +129,14 @@ async def execute(
                     module.id
                 )
 
-        # NOTE: When the estop is pressed, the gantry loses position,
-        # so the robot needs to home x, y to sync.
-        await ot3api.home(axes=[Axis.Z_L, Axis.Z_R, Axis.Z_G, Axis.X, Axis.Y])
+        # NOTE: When the estop is pressed, the gantry loses position, lets use
+        # the encoders to sync position.
+        # Ideally, we'd do a full home, but this command is used when
+        # the gripper is holding the plate reader, and a full home would
+        # bang it into the right window.
+        await ot3api.home(axes=[Axis.Z_L, Axis.Z_R, Axis.Z_G])
+        await ot3api.engage_axes([Axis.X, Axis.Y])
+        await ot3api.update_axis_position_estimations([Axis.X, Axis.Y])
 
         # Place the labware down
         await self._start_movement(ot3api, definition, location, drop_offset)