params learner unstable during dynamic driving

### Describe the bug

The params learner displays unexpected behavior when coming out of a corner, or accelerating or braking. The biggest problem seems to be going around corners in city driving, but acceleration or braking in a straight line can be a problem too.

When allowing the wheel to return to center under self-aligning torque, there is often a very large spike in learned tire stiffness along with some downward pressure on learned steering ratio. There are multiple issues:

* The params learner really only understands steady-state handling, not dynamic handling
* Therefore, steering return to center via self-aligning torque, unopposed by the driver, looks like really stiff tires
* Acceleration and braking also affect apparent tire stiffness for purposes of lateral control
* `car_kf` allows a big jump because ALL of its inputs jump simultaneously as we [cross below 45 degrees steering angle](https://github.com/commaai/openpilot/blob/cd8a603ad0f14d744d12e2f5f743c7880ce907a3/selfdrive/locationd/paramsd.py#L98-L99)

The effect seems to be cumulative, and can manifest as quality degrading over the course of a drive. Much of the effect doesn't persist for the next drive, because the [learned tire stiffness factor resets at the beginning of every drive](https://github.com/commaai/openpilot/blob/cd8a603ad0f14d744d12e2f5f743c7880ce907a3/selfdrive/locationd/paramsd.py#L166-L169), but effects on the learned steering ratio can persist.

I'm not sure of the best way to fix this. As a workaround, I've done some testing with a [patch that tries to exclude more dynamic driving](https://github.com/commaai/openpilot/commit/d01e0f8f7b7565e7f1043211a5d6ec4e7de74195). It's very crude and doesn't completely work, but does seem to reduce the problem somewhat. Anecdotally, the learned params with this patch do seem to have a positive effect on driving behavior.

### Provide a route where the issue occurs

04836f13759962ab/00000077--a510468422, 73adbb0a04418743/00000027--d30dd7b9db

### openpilot version

edd8759f3934b44c640d7d044bd0c383caf68a42 (today's master)

### Additional info

From my own car, `04836f13759962ab/00000077--a510468422`.


From Eyezenheim's car, `73adbb0a04418743/00000027--d30dd7b9db`.

**Note the tire stiffness factor transients, and the factor made it all the way to 1.5**.


**Return-to-center (falling below 45 degrees) transient example 1:**


**Return-to-center (falling below 45 degrees) transient example 2:**


**Return-to-center (falling below 45 degrees) transient example 3:**