Add UI changes to showcase the Mark as Resolved button

[LujainAlMansoori]

Description: This involved editing the front-end interface to add an additional button called "Mark as resolved" right below the "reply" button. along with casing on whether the API request depending on the value chosen(isResolved changes from false to true). This would allow instructors/owners to mark the posts as resolved.

Estimated effort: The effort required would be moderate, as it would involve modifying the front-end to display the button, and having the UI make the correct API request depending on the chosen value for the button.

Dependencies: This issue does not depend on another issue but is connected/builds upon issue #67

Acceptance criteria: Check if the UI is correctly showing a new button after posting a topic, and that depending on whether the button was clicked on or not we are seeing the correct API request being made. This could be checked by either looking at the logs to make sure the API request is being made or by looking at the network requests our browser is making.

Milestone: Sprint 2