Add return in report function of wrapper agent

[dianaglzrico]

Patch description
Agent was breaking because of missing return when calling report().

Testing steps
Unit test:

$ python -m unittest tests.test_wrapper
16:06:36 INFO | creating task(s): wrapper:labelToTextTeacher
.
----------------------------------------------------------------------
Ran 1 test in 0.092s

OK

As stated here this teacher doesn't (and is not expected to) pass python tests/datatests/test_new_tasks.py because of the nature of this task (read link's PR description for a more detailed explanation).

[github-actions]

Your PR contains a change to a task. Please paste the results of the following command into a comment:

python tests/datatests/test_new_tasks.py

[EricMichaelSmith]

Great catch! (Make sure to paste in the output from python tests/datatests/test_new_tasks.py :) )

[dianaglzrico]

Great catch! (Make sure to paste in the output from python tests/datatests/test_new_tasks.py :) )

added unittest and explanation!