Copter: guided: set_angle call init_z_controller when changing from thrust to climb rate control to avoid flow of control error

[IamPete1]

We init the Z controller when we fist enter the angle sub mode of guided. However if you send throttle commands the Z controller is not used, if you then change to sending climb rate commands while remaining in angle sub mode you trigger this flow of control error in the pos controller:

ardupilot/libraries/AC_AttitudeControl/AC_PosControl.cpp

Lines 961 to 969 in a9ea760

	// Check for z_controller time out
	if (!is_active_z()) {
	init_z_controller();
	if (has_good_timing()) {
	// call internal error because initialisation has not been done
	INTERNAL_ERROR(AP_InternalError::error_t::flow_of_control);
	}
	}
	_last_update_z_ticks = AP::scheduler().ticks32();

extract from #28110

[rmackay9]

I think this is very likely correct

[lthall]

Nice Catch

[rmackay9]

Thanks for this. The extra spaces above and below could be removed but in general it's OK to merge, thanks!

[IamPete1]

Thanks for this. The extra spaces above and below could be removed but in general it's OK to merge, thanks!

Spaces removed.