Hyundai: match cancel button panda safety logic

[sshane]

Closes #34203

This is to fix the problem where the logged button presses cause disengagement on pause/resume release with stock long. Still need a good way to support this with openpilot long, but that's lower priority as it doesn't jankily enable then disable in the first place, and long isn't in release

Stock long:

• Pressing cancel (pause/resume) enables as normal, letting go does not cancel

openpilot long:

• Pressing cancel is not considered an enable button and does not enable

This works by matching panda safety and not checking the cancel button when stock long is active, letting the radar handle both enabling and disabling.

[sshane]

panda safety across the brands is quite split on checking the cancel button if stock long is controlling or not, and the way this previously worked was Hyundai-specific in not adding the button events, so this seems like a decent solution until we make all the panda safety match each other (don't check when stock long?)

GM, VW PQ, and Hyundai only check cancel button with op long, so this PR makes Hyundai match panda safety.