[UI Feature] Explicitly define content-type as 'application/javascript' for requests to assets/main.js

[jsonporter]

Motivation: Why do you think this is important?

Requests with nosniff will fail when data requested is not the correct MIME type. While this is not an issue in most use cases/users, users behind proxies that add this header will be affected. However, user base aside, this is a best practice that we should implement regardless.

Acceptance Criteria:

• Requests should explicitly define MIME/content-type; type should be correct.

Goal: What should the final outcome look like, ideally?

MIME type for requests to /assets/main.js are served as application/javascript

Propose: Link/Inline OR Additional context

No response

Are you sure this issue hasn't been raised already?

• Yes

Have you read the Code of Conduct?

• Yes