Fix gi-formula issues and add index generation

[nguyentvan7]

Describe your changes

• Fix some issues with gi-formula (forgot to test the site before merging previous PR woops)
• Add index.ts generation as part of the sheet generator script

Issue or discord link

Testing/validation

• Tested and made sure characters with templated sheets still worked

Checklist before requesting a review (leave this PR as draft if any part of this list is not done.)

• I have commented my code, in hard-to understand areas.
• I have made corresponding changes to README or wiki.
• For front-end changes, I have updated the corresponding English translations.
• Ran yarn run mini-ci locally to validate format + lint.
• If there were format issues, I ran nx format write to resolve them automatically.

[github-actions]

[gi-frontend] [Thu Nov 30 16:51:13 UTC 2023] - Building version

[gi-frontend] [Thu Nov 30 16:53:55 UTC 2023] - Deployed bbbdea0 to https://genshin-optimizer-prs.github.io/pr/1353/gi-frontend (Takes 3-5 minutes after this completes to be available)

[gi-frontend] [Thu Nov 30 16:55:17 UTC 2023] - Building version 8d7e363

[gi-frontend] [Fri Dec 1 02:29:33 UTC 2023] - Building version ecb88f1

[gi-frontend] [Fri Dec 1 02:33:12 UTC 2023] - Building version 75f57de

[gi-frontend] [Fri Dec 1 02:35:38 UTC 2023] - Deployed 75f57de to https://genshin-optimizer-prs.github.io/pr/1353/gi-frontend (Takes 3-5 minutes after this completes to be available)

[gi-frontend] [Fri Dec 1 02:37:15 UTC 2023] - Building version 75f57de

[gi-frontend] [Fri Dec 1 02:39:37 UTC 2023] - Deployed 75f57de to https://genshin-optimizer-prs.github.io/pr/1353/gi-frontend (Takes 3-5 minutes after this completes to be available)

[gi-frontend] [Fri Dec 1 03:32:40 UTC 2023] - Building version 6a4e2a6

[gi-frontend] [Fri Dec 1 03:35:06 UTC 2023] - Deployed 6a4e2a6 to https://genshin-optimizer-prs.github.io/pr/1353/gi-frontend (Takes 3-5 minutes after this completes to be available)

[Fri Dec 1 19:28:00 UTC 2023] - Deleted deployment

[frzyc]

prob need to fix lint issues with traveler