<!--
Write a short description of the changes included in this pull request,
also include relevant motivation and context. Have in mind the following
questions:
1. What is the reason for the change?
2. What is the improvement/solution?
-->

Context:
https://consensys.slack.com/archives/C05HZHDS89Z/p1708946195217929
Pass origin as `metamask` for ppom validate request

Fixes:

1. Go to this page...
2.
3.

<!-- If applicable, add screenshots and/or recordings to visualize the
before and after of your change. -->

<!-- [screenshots/recordings] -->

<!-- [screenshots/recordings] -->

- [ ] I’ve followed [MetaMask Coding
Standards](https://github.com/MetaMask/metamask-mobile/blob/main/.github/guidelines/CODING_GUIDELINES.md).
- [ ] I've clearly explained what problem this PR is solving and how it
is solved.
- [ ] I've linked related issues
- [ ] I've included manual testing steps
- [ ] I've included screenshots/recordings if applicable
- [ ] I’ve included tests if applicable
- [ ] I’ve documented my code using [JSDoc](https://jsdoc.app/) format
if applicable
- [ ] I’ve applied the right labels on the PR (see [labeling
guidelines](https://github.com/MetaMask/metamask-mobile/blob/main/.github/guidelines/LABELING_GUIDELINES.md)).
Not required for external contributors.
- [ ] I’ve properly set the pull request status:
  - [ ] In case it's not yet "ready for review", I've set it to "draft".
- [ ] In case it's "ready for review", I've changed it from "draft" to
"non-draft".

- [ ] 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.