mc_att_control: revert to tested cutoff frequency

[MaEtUgR]

Revert the disabled d term filter which needs to be enabled
after reducing IMU filtering and was probably unintentionally
during a rebase.

Likely fixes #9150

[bkueng]

Thanks, I didn't realize that

[MaEtUgR]

More detailed explanation:

• Before MC rate controller: add low-pass filter for D-term #8920 the default cutoff frequency for the software filter for IMU was 30Hz
• After this pr the user was able too choose cutoff in general and cutoff for the d term of the rate controller separately. But the default was still 30Hz generall, separate D term filter disabled MC_DTERM_CUTOFF = 0.
• With Update IMU gyro and D term filter defaults #9070 the default was changed according to experiments with a variety of vehicles. The general cutoff for gyroscope was raised to 80Hz and the D term cutoff was enabled to 30Hz such that no D term noise gets to the output.
• In Multicopter mixer saturation handling strategy -- continue #9062 the D term cutoff was accidentally disabled again probably because of rebase conflicts resulting in a high general cutoff and nothing attenuating the D term noise.
• This possibly resulted in sudden unstable flight depending on vehicle and tuning with master and default parameters which was luckily spoted and reported by the test team in MultiRotor: Unstable manual flight #9150.

[bresch]

@MaEtUgR Thanks!

[santiago3dr]

https://logs.px4.io/plot_app?log=8933a3e8-c062-44a0-a9be-8c01eb725a7e

hotfix working; stable flight in manual