Hwdev 2399 feat use correct mm per pulse when tug connected

[ar90n]

ref: HWDEV-2399

This PR is motivated to add selecting mm_per_pulse depends on whether tug is connected or not and fix wrong error value handling in info sub command. This PR contains followings

• add a function whose name is get_mm_per_pulse to get suitable mm_per_pulse depends on whether tug is connected or not.
• Add displaying mm_per_sec in info sub command.
• Fix wrong value cast in info sub command, which is casting -1 into uint8_t.

This PR is tested in robots. And results are followings.

with tug

uart:~$ tug_encoder info
Angle: 74.882812[deg]
TUG connected: 1
Magnet detected: 0
Raw Angle: 0
Burn count: 3
ZPOS: 3244
MPOS: 3244
uart:~$ act info
[notice] parameter order [Center] [Left] [Right]
actuator: 0 encoder: -1 pulse current: 0 mV fail: 0 dir: 0 duty: 0 mm/pulse: 0.047438
actuator: 1 encoder: -1 pulse current: 0 mV fail: 0 dir: 0 duty: 0 mm/pulse: 0.003300
actuator: 2 encoder: -1 pulse current: 0 mV fail: 0 dir: 0 duty: 0 mm/pulse: 0.003300

without tug

uart:~$ tug_encoder info
Angle: 0.000000[deg]
TUG connected: 0
Magnet detected: 0
Raw Angle: -1
Burn count: -1
ZPOS: -1
MPOS: -1
[00:00:42.334,000] <wrn> tug_encoder: Failed to read ZMCO
[00:00:42.334,000] <wrn> tug_encoder: Failed to read AS5600_REG_RAW_ANGLE_H
[00:00:42.334,000] <wrn> tug_encoder: Failed to read AS5600_REG_ZPOS_H
[00:00:42.334,000] <wrn> tug_encoder: Failed to read AS5600_REG_MPOS_H
[00:00:42.337,000] <wrn> tug_encoder: Failed to read status
uart:~$ act info
[notice] parameter order [Center] [Left] [Right]
actuator: 0 encoder: -1 pulse current: 2 mV fail: 0 dir: 0 duty: 0 mm/pulse: 0.047438
actuator: 1 encoder: -1 pulse current: 0 mV fail: 0 dir: 0 duty: 0 mm/pulse: 0.047438
actuator: 2 encoder: -1 pulse current: 2 mV fail: 0 dir: 0 duty: 0 mm/pulse: 0.047438