This function retrieves the group categories for a specific context (e.g., course) in the Canvas LMS API.
     
    
    Usage
    get_group_categories(canvas, course_id)
 
    
    Arguments
- canvas
- A list containing the 'api_key' and 'base_url' for authentication. 
- course_id
- The ID of the course for which to retrieve the group categories. 
 
    
    Value
    A data frame of group categories in the specified context.