Fix asset file generation

[nguyentvan7]

Describe your changes

Asset file generation wasn't actually working, because of the improper use of .then(). Using proper async/await paradigm. Also removed an extra sort call since Prettier will just do it for us.

Issue or discord link

Testing/validation

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.
• [ ] I have run yarn run mini-ci locally to validate format and lint.
• [ ] If I have added a new library or app, I have updated the deployment scripts to ignore changes as needed

[github-actions[bot]]

[frontend] [Wed Jun 5 18:32:04 UTC 2024] - Deployed 0d16d662f43b38db77362f1ab663096c39aed8fa to https://genshin-optimizer-prs.github.io/pr/2208/frontend (Takes 3-5 minutes after this completes to be available)

[sr-frontend] [Wed Jun 5 18:33:20 UTC 2024] - Deployed 0d16d662f43b38db77362f1ab663096c39aed8fa to https://genshin-optimizer-prs.github.io/pr/2208/sr-frontend (Takes 3-5 minutes after this completes to be available)

[sr-frontend] [Wed Jun 5 18:59:10 UTC 2024] - Deployed 91a29dc131ba797e27bf9d8ddddd801d5df428c2 to https://genshin-optimizer-prs.github.io/pr/2208/sr-frontend (Takes 3-5 minutes after this completes to be available)

[frontend] [Wed Jun 5 18:59:53 UTC 2024] - Deployed 91a29dc131ba797e27bf9d8ddddd801d5df428c2 to https://genshin-optimizer-prs.github.io/pr/2208/frontend (Takes 3-5 minutes after this completes to be available)

[sr-frontend] [Thu Jun 6 23:05:09 UTC 2024] - Deployed ab3d28ac86c843ac69f0afa428eff76ee3aafa99 to https://genshin-optimizer-prs.github.io/pr/2208/sr-frontend (Takes 3-5 minutes after this completes to be available)

[frontend] [Thu Jun 6 23:05:31 UTC 2024] - Deployed ab3d28ac86c843ac69f0afa428eff76ee3aafa99 to https://genshin-optimizer-prs.github.io/pr/2208/frontend (Takes 3-5 minutes after this completes to be available)

[Sat Jun 8 06:24:17 UTC 2024] - Deleted deployment