Measure FPA focus position and update xcu.yaml if needed

We had to thermal cycle for the telescope maintenance (power panel upgrade work) late April. Check FPA focus and update xcu.yaml if needed.

Measured positions are as follows:

xcu_b1 motors moveCcd a=144.11 b=123.51 c=98.02 microns abs
xcu_b2 motors moveCcd a=218.95 b=229.08 c=219.80 microns abs
xcu_b3 motors moveCcd a=179.97 b=163.19 c=179.38 microns abs
xcu_b4 motors moveCcd a=110.23 b=73.24 c=124.67 microns abs

xcu_r1 motors moveCcd a=157.26 b=143.16 c=118.74 microns abs
xcu_r2 motors moveCcd a=154.91 b=177.78 c=156.43 microns abs
xcu_r3 motors moveCcd a=195.05 b=183.58 c=183.16 microns abs
xcu_r4 motors moveCcd a=97.29 b=43.97 c=90.85 microns abs

The motor (focus) positions changed by up to ~10um. As Image quality (spot size) of engineering fibers is the same as before with the above position, Use the new position.

Note: n arm show the similar spot size.