interfaces: Stock Longitudinal: Prevent disengagement on release of cancel button

[sunnyhaibin]

Description

• Currently, we are unable to use the PAUSE/RESUME button to re-engage openpilot due to a breaking change introduced in Hyundai: always publish cruise and main buttons opendbc#1326, which affects Hyundai/Kia/Genesis models using stock longitudinal control
• For some newer model years of Hyundai/Kia/Genesis cars using stock longitudinal control, the CANCEL button acts as a PAUSE/RESUME based on PCM state.
• Button events for Hyundai are now published continuously, leading to unintended disengagement on CANCEL button release.

Change

• For stock longitudinal control, the buttonCancel event now only triggers on the rising edge (button press) of the CANCEL button.
• openpilot longitudinal control continues to trigger buttonCancel on both press and release.

Verification

1. Disable openpilot longitudinal control, then start the car.
2. Engage openpilot by pressing the CRUISE MAIN button.
3. Cancel openpilot by pressing then releasing the PAUSE/RESUME button.
4. Resume openpilot by pressing then releasing the PAUSE/RESUME button.
5. Verify step 4 that openpilot stays engaged after the PAUSE/RESUME button is released.

Route

Route: 2bbe12792a30f61f/0000048c--f94b4ede96

[jyoung8607]

Since it traces back to #1326, I've requested review from @sshane.

I don't take a position on whether this PR is a correct fix.

[sshane]

Reverting the original PR as I'm not sure of the implications of not canceling on cancel press for other brands when stock long. There wasn't a real reason for it, it was only to log more data, which is still desired.

[sshane]

A proper fix would be to support the pause/resume button for openpilot longitudinal, do we have a PR for that somewhere?