Use logger error instead of exception (#1692)

Fixes the `Nonetype: None` issue that shows up in the logging.

It is caused by using `logging.exception` while not in an exception
handler.

I don't know whether including the full traceback makes sense in the
logging, but that could also be possible by adding `exc_info=exc`

connexion/middleware/exceptions.py

@@ -22,7 +22,7 @@ def __init__(self, next_app: ASGIApp):
 
     @staticmethod
     def problem_handler(_request: StarletteRequest, exc: ProblemException):
-        logger.exception(exc)
+        logger.error(exc)
 
         response = exc.to_problem()
 
@@ -35,7 +35,7 @@ def problem_handler(_request: StarletteRequest, exc: ProblemException):
 
     @staticmethod
     def http_exception(_request: StarletteRequest, exc: HTTPException) -> Response:
-        logger.exception(exc)
+        logger.error(exc)
 
         headers = exc.headers
 
@@ -52,7 +52,7 @@ def http_exception(_request: StarletteRequest, exc: HTTPException) -> Response:
 
     @staticmethod
     def common_error_handler(_request: StarletteRequest, exc: Exception) -> Response:
-        logger.exception(exc)
+        logger.error(exc)
 
         response = InternalServerError().to_problem()