ci(codeowners): add privacy reviewers to codeowners (MetaMask#21241)

## **Description**
Further locks down the privacy snapshot by adding codeowners for the
snapshot file. A new team for this was created by @danjm
@MetaMask/extension-privacy-reviewers

## **Manual testing steps**
1. In theory if you branch off this PR and change the codeowners, then
push up your branch you'll see that the team has been added to the PR as
a codeowner.

## **Pre-merge author checklist**

- [x] I’ve followed [MetaMask Coding
Standards](https://github.com/MetaMask/metamask-extension/blob/develop/.github/guidelines/CODING_GUIDELINES.md).
- [x] I've clearly explained:
  - [x] What problem this PR is solving.
  - [x] How this problem was solved.
  - [x] How reviewers can test my changes.
- [x] I’ve indicated what issue this PR is linked to: Fixes #???
- [x] I’ve included tests if applicable.
- [x] I’ve documented any added code.
- [x] I’ve applied the right labels on the PR (see [labeling
guidelines](https://github.com/MetaMask/metamask-extension/blob/develop/.github/guidelines/LABELING_GUIDELINES.md)).
- [x] I’ve properly set the pull request status:
  - [ ] In case it's not yet "ready for review", I've set it to "draft".
- [x] In case it's "ready for review", I've changed it from "draft" to
"non-draft".

## **Pre-merge reviewer checklist**

- [ ] I've manually tested the PR (e.g. pull and build branch, run the
app, test code being changed).
- [ ] I confirm that this PR addresses all acceptance criteria described
in the ticket it closes and includes the necessary testing evidence such
as recordings and or screenshots.

.github/CODEOWNERS

@@ -24,6 +24,17 @@ lavamoat/                            @MetaMask/extension-devs @MetaMask/supply-c
 # should be brought to the attention of engineering leadership for
 # discussion
 .circleci/                           @MetaMask/library-admins @kumavis @brad-decker
+
+# The privacy-snapshot.json file includes a list of all hosts that the
+# extension communicates with during the E2E test suite runs. It is not a
+# complete list of all hosts that the extension communicates with until the E2E
+# test suite has full coverage. Anytime the privacy-snapshot file changes,
+# extra scrutiny should be applied to the pull request to confirm that it does
+# not broaden the number of hosts the extension communicates with without also
+# providing a path for users to avoid that communication. MetaMask strives to
+# make all such communication opt IN versus opt OUT.
+privacy-snapshot.json                @MetaMask/extension-privacy-reviewers
+
 # The CODEOWNERS file constitutes an agreement amongst organization
 # admins and maintainers to restrict approval capabilities to a subset
 # of contributors. Modifications to this file result in a modification of