Fix freelook being replaced with a Java exception

[aphedges]

Fixes #25.

When running task-7-identify-life-stages-1, focusing on an inanimate object would cause freelook, inventory, and observation to be replaced with "java.util.NoSuchElementException: None.get" instead of the proper value. This was caused by not checking whether an Option variable was set before trying to retrieve one of its variables. It only happened as part of console output, so it was safe to make the println statement conditional on whether the variable was set.

I used the following script for testing:

from scienceworld import ScienceWorldEnv

env = ScienceWorldEnv("")
env.load("task-7-identify-life-stages-1", 7, "")
env.step("open door to kitchen")
env.step("go to kitchen")
*_, info = env.step("focus on thermometer")
print(repr(info["look"]))

Before this commit, I get the following output:

'java.util.NoSuchElementException: None.get'

After this commit, I get the following output:

'This room is called the kitchen. In it, you see: \n\tthe agent\n\ta substance called air\n\ta chair. On the chair is: nothing.\n\ta counter. On the counter is: a bowl (containing a red apple, a banana, an orange, a potato), a drawer.\n\ta cupboard. The cupboard door is closed. \n\ta freezer. The freezer door is closed. \n\ta fridge. The fridge door is closed. \n\ta glass jar (containing a substance called sodium chloride)\n\ta lighter\n\ta oven, which is turned off. The oven door is closed. \n\ta painting\n\ta sink, which is turned off. In the sink is: nothing.\n\ta substance called soap\n\ta stopwatch, which is deactivated. \n\ta stove, which is turned off. On the stove is: nothing.\n\ta table. On the table is: a glass cup (containing nothing).\n\ta thermometer, currently reading a temperature of 10 degrees celsius\nYou also see:\n\tA door to the bathroom (that is closed)\n\tA door to the hallway (that is open)\n\tA door to the outside (that is closed)\n'

[PeterAJansen]

Should be a very minor change and not impact anything. Thanks for the contribution!