Fixes for MultipleChoiceOption and FeedbackOption API

This merge request fixes two things:

1. Deleting a FeedbackOption will now throw an error if it is coupled to a MultipleChoiceOption
2. Inserting a MultipleChoiceOption will now check the problem_id parameter to see if an actual Problem with the specified problem_id exists.

Fixes #51 (closed) and #55 (closed)

Note: It might be useful to merge !16 (merged) first, since I can write test code for this MR.

changed title from WIP: Several fixes for MultipleChoiceOption API to WIP: Fixes for MultipleChoiceOption and FeedbackOption API

changed the description

Fixes #51 (closed) and #55 (closed)

Both fixes look good to me!

changed the description

resolved all discussions

added 21 commits

• 551d9807...ea611c95 - 20 commits from branch develop
• b63c9fa8 - Fixed conflicts, and added test for feedback deletion

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unmarked as a Work In Progress

added 1 commit

• 6b556fda - Added test for feedback deletion

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added 1 commit

• 5eae9d3b - Changed added test for deleting feedback options, improved mc_options test

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added 1 commit

• 60181548 - Fixed lint warning

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added 33 commits

• 60181548...9df3d26b - 32 commits from branch develop
• 4e06a1f0 - Resolved conflicts with develop

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An error notification still needs to be shown in the frontend.

Continues in #52 (closed).

mentioned in commit 78196d7b

merged