Description

Related PRS (if any):

This PR is related backend PR #1877

Main changes explained:

• Created an assign atoms modal with a search bar to select students and a checkbox list to select atom assignments.
• Created a new standalone page to test working of the modal.

How to test:

1. check into current branch
2. do yarn install and yarn start to run this PR locally
3. Clear site data/cache
4. log as admin user
5. go to http://localhost:5173/educationportal/assignatoms
6. Click the Assign Atoms button
7. Type in your user or select any user from the dropdown for student
8. Select any number of atoms to be assigned to that student
9. Add an optional note
10. Click on submit and verify that you receive a success toast message.

Screenshots or videos of changes: