AP_Parachute: Optional (CHUTE_OPTIONS:1) disarm before parachute release

[python36]

Based on discussion of PR #25570 and #25562.

Disarm before parachute release to avoid parachute tangling if parameter CHUTE_OPTIONS:1 = 0.

[IamPete1]

We have a option to enable safety switch on disarm, if that was set disarm would cause safety to come on which could in-turn inhibit your parachute release servo.

I'm not really sure how we can overcome that. It maybe such a edge case that is does not matter. Of course it only affects those methods that don't currently disarm.

[python36]

Hi @IamPete1 . Please write a set of parameters and actions that will lead to this. I have tested many cases and cannot inhibit the parachute servo with the safety buttons.

[tridge]

if that was set disarm would cause safety to come on which could in-turn inhibit your parachute release servo.

@IamPete1 we currently always disarm on release, so this is adding an option to not do that. The exact order is likely not important as setting the PWM for a server isn't instantaneous anyway

[tridge]

I think this is good, marked for dev call topic for discussion

[tridge]

@Hwurzburg for docs, we need to note that BRD_SAFETY_MASK needs to be setup to allow chute servo when disarmed if you have the option to set safety on when you disarm

[IamPete1]

LGTM. Note that there is a change in behavior in plane battery fail-safe case where we would previously not disarm.

[peterbarker]

Needs a split

[rmackay9]

We should fix the commit message.

[tridge]

I split the commits into subsystems and rebased

[python36]

Many thanks