Resolve issue #13054

[Shibui-Li-1998]

Fixes TEAMMATES#13054

Outline of Solution

1. Code Change Location:

The following files were updated to implement the feature:

• src/web/app/components/question-submission-form/question-submission-form.component.html
• src/web/app/components/question-submission-form/question-submission-form.component.ts
• src/web/app/components/question-submission-form/question-submission-form.component.spec.ts

2. Details of the Changes:

• Added a text input field above the dropdown student list to facilitate search.
• Implemented logic to allow users to search for students by entering substrings of their names.
• Manually tested the new feature by inputting various substrings to ensure accurate search functionality.
• Added new test cases to cover the updated functionality.

3. Demonstration:

Before:

After:

[github-actions]

Hi @Shibui-Li-1998, thank you for your interest in contributing to TEAMMATES!
However, your PR does not appear to follow our contribution guidelines:

• Title must start with the issue number the PR is fixing in square brackets, e.g. [#<issue-number>]

Please address the above before we proceed to review your PR.

[Shibui-Li-1998]

I have checked the codes and there is no conflicts.

[Yokyeee1114]

I have checked the code and it is ok to merge