Updated Docs for pack application

[saurabha994]

Why:

Updated docs to reflect change in Github Education pack application for the role of students and teachers.

What's being changed (if available, include any code snippets, screenshots, or gifs):

Made change to add an additional step of selecting a role while filling the application.

Check off the following:

• I have reviewed my changes in staging (look for the "Automatically generated comment" and click the links in the "Preview" column to view your latest changes).
• For content changes, I have completed the self-review checklist.

Writer impact (This section is for GitHub staff members only):

• This pull request impacts the contribution experience
  • I have added the 'writer impact' label
  • I have added a description and/or a video demo of the changes below (e.g. a "before and after video")

[cmwilson21]

👋 @saurabha994 - Thanks so much for opening a PR! I'll get this triaged for review ⚡

[mattpollard]

Thanks, @saurabha994! ✨ I'll address the merge conflicts, incorporate a couple of small changes, and merge this for you.

Edit: Update below 👇🏻

[mattpollard]

👋🏻 @saurabha994, sorry for the delay. I was having a bit of trouble pushing to your branch.

Unfortunately, the file you modified no longer exists. I'm thinking perhaps main in your local clone of github/docs was a couple of months old.

The content you need to modify is now in this file, which you can see on the main branch. You’ll need to merge main into your branch, and apply your change from apply-for-an-educator-or-researcher-discount.md to github-global-campus-for-teachers/apply-to-github-global-campus-as-a-teacher.md instead when you go to resolve the merge conflict.

Let me know if you have questions! 🙏🏻

[saurabha994]

Closing this in favour of another PR.