Hide course list (student/teacher) on My Page if no courses

[hisahi]

Short description

1021

DoD

I have:

• [x] added actual code.
• [x] produced clean code that passes ESLint.
• [x] code that actually does what it should.
• [ ] documented the code or added documentation to the wiki.
• [ ] added or modified test(s).
• [x] test(s) that actually pass.

[Mamelukki]

It still shows the segment even if the user has no courses at all. Maybe the segment should be hidden in that case too?