AC_AttitudeControl use const where possible

[lthall]

This is addressing the feedback that I have missed a number of locations where I should be using const.

Intended to go in after #30164

Board,blimp,bootloader,copter,heli,plane,rover,sub
CubeOrange,*,*,*,*,*,*,*

[peterbarker]

Conflicting now.

I was going to do that as part of the PR I just merged but didn't want to introduce merge conflicts with your other PR.

... I was going to suggest const on that other PR where we are modifying these lines anyway to change radians(ang)*0.01 to ang*radians(0.01)

[rmackay9]

LGTM, thanks

[peterbarker]

Board                    AP_Periph  blimp  bootloader  copter  heli  iofirmware  plane  rover  sub
CubeOrange-periph-heavy  *                 *                                                   
CubeRedPrimary                      *      *           *       *                 *      *      *
Durandal                            *      *           *       *                 *      *      *
Hitec-Airspeed           *                 *                                                   
KakuteH7-bdshot                     *      *           *       *                 *      *      *
MatekF405                           *      *           *       *                 *      *      *
Pixhawk1-1M-bdshot                  *                  *       *                 *      *      *
f103-QiotekPeriph        *                 *                                                   
f303-Universal           *                 *                                                   
iomcu                                                                *                         
revo-mini                           *      *           *       *                 *      *      *
skyviper-journey                                       *                                       
skyviper-v2450                                         *