Summary:
PR #486 changed propagation to track each object independently. This allows to add objects after the initial propagation.
The frontend has a constraint that would prevent users from adding new objects after the initial "tracking". Now that the model supports tracking objects independently, we can remove this constraint from the UI.
Test Plan:
`cd demo/frontend`
`yarn lint`
```
(base) ➜ demo/frontend $ yarn lint ⎇ remotes/origin/HEAD*
yarn run v1.18.0
$ eslint . --ext ts,tsx --report-unused-disable-directives --max-warnings 0
✨ Done in 16.98s.
```
This PR update repo links after we renamed the repo from `segment-anything-2` to `sam2`. It also changes `NAME` in setup.py to `SAM-2` (which is already the named used in pip setup since python packages don't allow whitespace)
