Observer doesn't detect curved rail changing direction

Bug description

Observers cannot detect a corner rail switching its direction. This is because the rail state change does not cause a block update, which is required for observers in Bedrock to activate. I think rail-switching should cause block updates.

Steps to reproduce

1. Build a rail intersection, with a corner rail placed on top of an observer whose output is facing downward into redstone wire directly below the observer.
2. Power the corner rail using redstone. Notice that the observer doesn't activate.