chore: add profileId to position response

[joaosantos15]

Explanation

Add profileId to position response.

References

Checklist

• I've updated the test suite for new or updated code as appropriate
• I've updated documentation (JSDoc, Markdown, etc.) for new or updated code as appropriate
• I've communicated my changes to consumers by updating changelogs for packages I've changed
• I've introduced breaking changes in this PR and have prepared draft pull requests for clients and consumer packages to resolve them

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Note

Low Risk
Low risk: this is a type/response-validation schema expansion for positions plus test fixture updates, with no behavioral or endpoint changes. Main risk is consumers now needing to include positionId in mocked/expected position payloads to pass validation.

Overview
Positions returned by SocialService now require a new positionId field via updates to the Position type and the PositionStruct superstruct schema.

Tests and the package changelog are updated accordingly to reflect and validate the new field.

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[joaosantos15]

@metamaskbot publish-preview