Fix monkeypatch.setattr/delattr binding descriptors with raising=False

[IMGillusion]

When raising=False, the attribute existence check now reads the attribute statically (inspect.getattr_static) instead of using getattr/hasattr, so descriptors are no longer bound during the check and their __get__ side effects do not fire.

closes #10646

Problem

monkeypatch.setattr/delattr with raising=False used getattr/hasattr to probe whether the attribute exists. That binds any descriptor on the target (invoking its __get__), triggering __get__ side effects purely as a side effect of the existence check.

Fix

When raising=False, probe the attribute statically with inspect.getattr_static, which reads the attribute without binding descriptors. raising=True keeps the previous behaviour (binding is intentional there).

Tests

Adds regression tests in testing/test_monkeypatch.py using a RaisingDescriptor whose __get__ raises, asserting the descriptor is bound with raising=True but not with raising=False, for both setattr and delattr (class and instance targets).