Fixed ResourceWarnings in tests (#1366)

* #1320 Update pytest configuration and tests cleanup

This commit modifies the pytest's configuration file, `pyproject.toml`, to remove filterwarnings settings. It also makes changes in various test files; the Redis isolation test is now using the provided `redis_storage` fixture instead of setting up its own connection, pytest.mark.filterwarnings is no longer used in `test_isolation.py` and `test_aiohttp_session.py` properly closes off sessions.

* Added changelog

* Fixed coverage for the RedisEventIsolation

pyproject.toml

@@ -237,10 +237,9 @@ asyncio_mode = "auto"
 testpaths = [
     "tests",
 ]
-filterwarnings = [
-    "error",
-    "ignore::pytest.PytestUnraisableExceptionWarning",
-]
+#filterwarnings = [
+#    "error",
+#]
 
 [tool.coverage.run]
 branch = false