mission: reset work_item_type during mission inactivation
mission: reset work_item_type during mission inactivation

- this fixes a race condition which happens when an RTL is triggered
during the final approach of a mission landing. In that case the mission inactive
method is never called.

Signed-off-by: RomanBapst <019237760eff64d50a7eec108f84e3d8840aac17@gmail.com>

acfloria/Firmware,acfloria/Firmware,acfloria/Firmware,acfloria/Firmware,acfloria/Firmware,acfloria/Firmware,acfloria/Firmware