refactor(azure): wrap pull request queries

[zharinov]

Changes

Wrap Azure pull request queries in a repository-local helper with named options. The helper maps those options to the generated Azure SDK's positional parameters in one place. Query criteria, pagination, authentication, and returned values remain unchanged.

This draft is based on #45359 and must merge after it. Until #45359 lands, commit 0c2ebc2e0 is the refactor-only diff.

Context

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