Add Pick Cube waypoint

It is used by "3 Waypoints Pick and Place" but was removed accidetally
in an earlier change

src/lab_sim/waypoints/ur_waypoints.yaml

@@ -901,3 +901,46 @@
     twist: []
     wrench: []
   name: Beaker 2a - Pre Pick
+- description: ''
+  favorite: false
+  joint_group_names:
+    - gripper
+    - linear_actuator
+    - manipulator
+  joint_state:
+    effort: []
+    header:
+      frame_id: ''
+      stamp:
+        nanosec: 0
+        sec: 0
+    name:
+      - robotiq_85_left_knuckle_joint
+      - linear_rail_joint
+      - shoulder_pan_joint
+      - shoulder_lift_joint
+      - elbow_joint
+      - wrist_1_joint
+      - wrist_2_joint
+      - wrist_3_joint
+    position:
+      - 0.06656709575770764
+      - 0.2544520984236789
+      - 0.00297097958947393
+      - -0.5454836524482858
+      - 1.028930149174636
+      - -2.02088483587436
+      - -1.5709145918870968
+      - 0.002734726536987722
+    velocity: []
+  multi_dof_joint_state:
+    header:
+      frame_id: ''
+      stamp:
+        nanosec: 0
+        sec: 0
+    joint_names: []
+    transforms: []
+    twist: []
+    wrench: []
+  name: Pick Cube