Modify Difficulty Dropdown: Align Elements and Add missing 'Medium' Option on web.

# Description
## Issue Summary:
- The "Difficulty" dropdown required significant updates for better usability and clarity. Previously, the dropdown lacked a proper label, making it unclear what the dropdown represented. Additionally, the "Medium" option was missing, and the layout had the label above the dropdown instead of being side by side.

## Expected Behavior:

- A proper "Difficulty" label should clearly describe the purpose of the dropdown.
- The "Difficulty" label and dropdown should be displayed side by side for better visual alignment.
- The "Medium" option should be available in the dropdown menu along with "Easy" and "Hard."

## Observed Behavior:

- No label was present for the "Difficulty" dropdown, making its purpose unclear.
- The "Difficulty" label appears above the dropdown.
- The "Medium" option is missing from the dropdown menu.

## Present Page :