fix(postgres): make transitive gets default to parent schema

[vanthome]

Make index-creation work also if the schema is provided at sync time.

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• [x] Does npm run test or npm run test-DIALECT pass with this change (including linting)?
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• [x] Have you added new tests to prevent regressions?
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Description of change

Fixes #11638, #11634

[robert-niestroj]

Please merge this. We need this in our project.