position control reset tilt limit and hover thrust in non-position mode

[NicolasM0]

Solved Problem

When flying in non position mode, the position control tilt limit is not updated.
Taking off in another mode (in my case offboard attitude control) and changing to a position control mode during flight (in my case pilot take over by RC in position mode) will result in tilt clamping following the takeoff slew rate.

Solution

Update the tilt limit slew rate even if not in position mode ("flag_multicopter_position_control_enabled") as if it was.

With the same reasoning, I have also added a condition to reset the hover thrust as done in position control mode.

Test coverage

• developed and tested on older branch
• back ported here and test in SITL