Fix compatibility with pytest 8.2 FixtureDef.unittest removal

Since pytest 8.2 unittest and regular behave the same, so unittest
special handling is no longer needed.

pytest_asyncio/plugin.py

@@ -316,8 +316,9 @@ def _wrap_asyncgen_fixture(fixturedef: FixtureDef, event_loop_fixture_id: str) -
 
     @functools.wraps(fixture)
     def _asyncgen_fixture_wrapper(request: FixtureRequest, **kwargs: Any):
+        unittest = False if pytest.version_tuple >= (8, 2) else fixturedef.unittest
         func = _perhaps_rebind_fixture_func(
-            fixture, request.instance, fixturedef.unittest
+            fixture, request.instance, unittest
         )
         event_loop = kwargs.pop(event_loop_fixture_id)
         gen_obj = func(
@@ -355,8 +356,9 @@ def _wrap_async_fixture(fixturedef: FixtureDef, event_loop_fixture_id: str) -> N
 
     @functools.wraps(fixture)
     def _async_fixture_wrapper(request: FixtureRequest, **kwargs: Any):
+        unittest = False if pytest.version_tuple >= (8, 2) else fixturedef.unittest
         func = _perhaps_rebind_fixture_func(
-            fixture, request.instance, fixturedef.unittest
+            fixture, request.instance, unittest
         )
         event_loop = kwargs.pop(event_loop_fixture_id)