POC(liveness): allow back camera selection

[esauerbo]

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• [ ] Have read the Pull Request Guidelines
• [ ] PR description included
• [ ] yarn test passes and tests are updated/added
• [ ] PR title and commit messages follow conventional commit syntax
• [ ] If this change should result in a version bump, changeset added (This can be done after creating the PR.) This does not apply to changes made to docs, e2e, examples, or other private packages.

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