[#12588] Improve test code coverage of QuestionEditDetailsForm

[rushithapenikalapati]

Part of #12588

Outline of Solution

I added unit tests for all of the sections highlighted in red for the src/web/app/components/question-types/question-edit-details-form/constsum-options-question-edit-details-form.component.spec.ts file.

[cedricongjh]

hi @rushithapenikalapati, thank you for your PR, do fix the failing tests before we proceed to review it

also do refer to the guidelines here: https://teammates.github.io/teammates/unit-testing.html for writing unit tests, at a glance it appears that the method name is missing from the test descriptor strings, do add that in, thank you!

[weiquu]

Closing due to inactivity