Copter: add and use new afs_mode mode method

[IamPete1]

Another extract from #28110. This removes as mode number switch and replaces with a mode method that returns the advanced failsafe mode category.

[peterbarker]

LGTM

[amilcarlucas]

Binary Name      Text [B]     Data [B]     BSS (B)      Total Flash Change [B] (%)      Flash Free After PR (B)
---------------  -----------  -----------  -----------  ----------------------------  -------------------------
arducopter       0 (0.0000%)  0 (0.0000%)  0 (0.0000%)  0 (0.0000%)                                      154072
antennatracker   0 (0.0000%)  0 (0.0000%)  0 (0.0000%)  0 (0.0000%)                                      624516
arducopter-heli  0 (0.0000%)  0 (0.0000%)  0 (0.0000%)  0 (0.0000%)                                      155024
ardusub          0 (0.0000%)  0 (0.0000%)  0 (0.0000%)  0 (0.0000%)                                      363516
ardurover        0 (0.0000%)  0 (0.0000%)  0 (0.0000%)  0 (0.0000%)                                      305536
blimp            0 (0.0000%)  0 (0.0000%)  0 (0.0000%)  0 (0.0000%)                                      602440
arduplane        0 (0.0000%)  0 (0.0000%)  0 (0.0000%)  0 (0.0000%)                                      156752

[IamPete1]

Binary Name      Text [B]     Data [B]     BSS (B)      Total Flash Change [B] (%)      Flash Free After PR (B)
---------------  -----------  -----------  -----------  ----------------------------  -------------------------
arducopter       0 (0.0000%)  0 (0.0000%)  0 (0.0000%)  0 (0.0000%)                                      154072
antennatracker   0 (0.0000%)  0 (0.0000%)  0 (0.0000%)  0 (0.0000%)                                      624516
arducopter-heli  0 (0.0000%)  0 (0.0000%)  0 (0.0000%)  0 (0.0000%)                                      155024
ardusub          0 (0.0000%)  0 (0.0000%)  0 (0.0000%)  0 (0.0000%)                                      363516
ardurover        0 (0.0000%)  0 (0.0000%)  0 (0.0000%)  0 (0.0000%)                                      305536
blimp            0 (0.0000%)  0 (0.0000%)  0 (0.0000%)  0 (0.0000%)                                      602440
arduplane        0 (0.0000%)  0 (0.0000%)  0 (0.0000%)  0 (0.0000%)                                      156752

Advanced failsafe is not enabled by default, hence the 0 cost. For CubeOrange this costs 72 bytes.

[rmackay9]

I can't say that I'm a huge fan of AFS spreading out into the mode library like this. Sorry, I've never liked how it's (not) integrated with our other failsafes so I prefer it be kept separate where possible.

[IamPete1]

I can't say that I'm a huge fan of AFS spreading out into the mode library like this. Sorry, I've never liked how it's (not) integrated with our other failsafes so I prefer it be kept separate where possible.

Yeah, its not great. But to enable custom modes we have to remove all switches using mode numbers. Doing it this way means that custom modes will inherit the behavior from guided mode.