Send SDK source data from JavaScript SDKs

[AbhiPrasad]

Problem Statement

Send if package is used via CDN, NPM, or loader.

Prev attempt: #6256

Parent issue: getsentry/sentry#43427

Solution Brainstorm

### Tasks
- [x] https://github.com/getsentry/sentry-javascript/pull/6904
- [x] https://github.com/getsentry/sentry-javascript/pull/6976
- [ ] https://github.com/getsentry/sentry-javascript/pull/6985