Fearscape right-click menu error fix

Fixes a Lua error with Fearscape, caused by a missing check on block_path in the engine.

From RedPopsicle in the discord, reproduced by myself and Moasseman:

The order is this:

1. Use Fearscape on target

2. Right click target while in Fearscape

3. Hover over Fearscape ability in right-click menu

4. Game freezes