[docs] Review HTTP opt-out portal links in cookie policy

# [docs] Review HTTP opt-out portal links in cookie policy

The cookie policy contains third-party opt-out portal links that still use `http://`. Since this is a policy/legal page, it may be better to review and update these separately from regular docs link cleanup.

Checked against upstream `base/docs` HEAD:

```text
5735457f14fb940f749bbc0d0059128648c8c5b6
```

## Findings

- `docs/cookie-policy.mdx:79`
- Current: `http://optout.aboutads.info/`
- Suggested: verify whether `https://optout.aboutads.info/` is the correct canonical target

- `docs/cookie-policy.mdx:81`
- Current: `http://optout.networkadvertising.org/?c=1`
- Suggested: verify whether `https://optout.networkadvertising.org/?c=1` is the correct canonical target

## Why separate

These links are in a cookie policy page and point to third-party advertising/privacy opt-out portals. Updating them may require checking whether the legal/policy wording should preserve canonical external references.