Added tests for SolutionComments

...rc/components/submission_type/SubmissionTypesOverview.vue

...tend/src/components/submission_type/solution/Solution.vue

...c/components/submission_type/solution/SolutionComment.vue

functional_tests/test_auto_logout.py

functional_tests/test_feedback_update.py

functional_tests/test_front_pages.py

functional_tests/test_solution_comments.py

functional_tests/util.py