Can't grab a solid vehicle while boarding it

[ShnitzelX2]

Summary

Bugfixes "can't grab a solid vehicle while boarding it"

Purpose of change

Yet another follow-up to #76338. The player shouldn't be able to push solid vehicles (e.g. cars) from the inside.

Describe the solution

Checks if vehicle is boarded, then if the vehicle is solid and the grabbed vehicle is the same as the boarded vehicle.

Fixes a bad comparison (using om_id, which was dumb) I made in #76338 that was vital to being able to test this.

Describe alternatives you've considered

Testing

Tested dragging a car normally, attempting to grab a car from the driver's seat and failing, attempting to grab a separate car from the first car and succeeding.

Additional context