L-TLM mixer pin fix

In my case, one pin is cracked but stays in place. This fix supports both pins so they cannot crack more.

Print model in vase mode with no bottom layers. Use 1 mm extrusion width. Use PETG, don't use PLA (motor gets hot).

Steps:

1. Print the model
2. Remove (pop up) bottom shiny ring (use screwdriver), don't remove other parts
3. Pull both halves (black plastic) from each other. You have to break pins inside that are approx. in the middle on both sides. There's no way to save them and it does not matter.
4. Pull front halve from the top shiny ring.
5. Lift motor
6. Place the printed part
7. Return the removed halve (it's tricky)
8. Check flexibility of pins - mount attachment
9. Push the ring back