🐛 Fix: 修复 dotenv 配置项为 None 将会跳过赋值 (#2143)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Ju4tCode <42488585+yanyongyu@users.noreply.github.com>

tests/test_init.py

@@ -20,6 +20,11 @@ async def test_init():
     assert env == "test"
 
     config = nonebot.get_driver().config
+    assert config.nickname == {"test"}
+    assert config.superusers == {"test", "fake:faketest"}
+    assert config.api_timeout is None
+
+    assert config.simple_none is None
     assert config.config_from_env == {"test": "test"}
     assert config.config_override == "new"
     assert config.config_from_init == "init"