[SYNPY-1870] Rewrite test_caching.py to not use deprecated legacy code

[andrewelamb]

Problem:

The integration test tests/integration/synapseclient/core/test_caching.py was written against the legacy pre-OOP API and emitted a large number of DeprecationWarnings (all slated for removal in 5.0.0) on every run. Running the test produced warnings for the legacy Project/File/Entity classes, Synapse.store, Synapse.get, Synapse.getChildren, and — indirectly, through the store path — Synapse.findEntityId, along with the internal legacy machinery those calls fanned out to (_getEntityBundle, _check_entity_restrictions, _getWithEntityBundle_async, Annotations/set_annotations, download_file_entity).

While migrating the test off the deprecated public API, the findEntityId warning turned out to originate in production code, not the test: synapseclient/models/services/search.py::get_id() (used by every model store/get for name+parent resolution) still called the deprecated Synapse.findEntityId via an asyncio executor shim, carrying a # TODO: SYNPY-1623 marker. So the OOP models themselves were still routing through a deprecated method.

Solution:

Migrated the test to the object-oriented models and operations layer, and fixed the underlying production code path so the models no longer depend on a deprecated method.

• tests/integration/synapseclient/core/test_caching.py:
  • Project/File now come from synapseclient.models instead of the legacy root classes.
  • syn.store(...) / syn.get(...) replaced with the model methods entity.store(synapse_client=syn) / entity.get(synapse_client=syn) (and File(id=id).get(...) for fetch-by-id).
  • syn.getChildren(...) replaced with synapseclient.api.get_children driven through wrap_async_generator_to_sync_generator (the same sync-consumption helper the StorableContainer mixin uses), since the workers run in sync executor threads. This preserves the lightweight "list child IDs" behavior rather than switching to the heavier sync_from_synapse (which would download files and change what the test exercises).
• synapseclient/models/services/search.py:
  • get_id() now calls find_entity_id_async (per the deprecation guidance, from synapseclient.operations import find_entity_id), replacing the deprecated findEntityId + run_in_executor shim. The async variant is used because get_id is a coroutine; it is imported lazily to avoid an operations → models → search circular import (mirroring how find_entity_id_async itself lazily imports api.get_child).
  • Removed the now-unused import asyncio and the SYNPY-1623 TODO, and updated the docstring reference. Behavior is equivalent: find_entity_id_async resolves the parent via id_of() and calls api.get_child, which supports parentId=None for the Project-by-name lookup — matching the old findEntityId(name, parent) contract.

This resolves the SYNPY-1623 tech debt as a side effect. get_id() has callers across project, folder, file, link, recordset, and table_components; the signature and return contract are unchanged, so all callers are unaffected.

Testing:

• Ran the affected unit tests before the production change to confirm the failure mode: 7 tests in unit_test_project_async.py / unit_test_folder_async.py failed with pytest_socket.SocketBlockedError because they mocked Synapse.findEntityId, which get_id no longer calls (the real get_child attempted a network call).
• Updated those tests to mock the new dependency (patch("synapseclient.operations.find_entity_id_async", new_callable=AsyncMock, ...)) and to include synapse_client=self.syn in the corresponding assert_called_once_with assertions.
• After the fix: 83 passed across the two model test files, and 1185 passed across tests/unit/synapseclient/models/ and tests/unit/synapseclient/operations/.
• Verified that importing the model store/get path with DeprecationWarning promoted to an error raises nothing, and confirmed no circular import from the lazy find_entity_id_async import.

[linglp]

LGTM! Just some minor comments.