test: Fix pytest error (#2712)

The ability to pass None to pytest.capture_warnings was removed in pytest version 8.0.0. To validate that this fix, one can run any of the test cases with pytest==8.0.0. Without this change, the test immediately fails with an error; with the change, the test suite runs as expected.

Fixes GH-2693

tests/__init__.py

@@ -1,6 +1,5 @@
 import sys
-
-import pytest
+import warnings
 
 # This is used in _capture_internal_warnings. We need to run this at import
 # time because that's where many deprecation warnings might get thrown.
@@ -9,5 +8,5 @@
 # gets loaded too late.
 assert "sentry_sdk" not in sys.modules
 
-_warning_recorder_mgr = pytest.warns(None)
+_warning_recorder_mgr = warnings.catch_warnings(record=True)
 _warning_recorder = _warning_recorder_mgr.__enter__()