Fix configuring loggers found in 'PREFECT_LOGGING_EXTRA_LOGGERS'

Each logger defined in 'PREFECT_LOGGING_EXTRA_LOGGERS' now has their level set according to the 'prefect.extra' level. Previously, this only occurred when their level was NOTSET.

Additionally, avoid configuring the logger 'level' and 'propagate' values while iterating over 'extra_config.handlers'

Resolves #15370

src/prefect/logging/configuration.py

@@ -94,12 +94,11 @@ def setup_logging(incremental: Optional[bool] = None) -> dict[str, Any]:
 
     for logger_name in PREFECT_LOGGING_EXTRA_LOGGERS.value():
         logger = logging.getLogger(logger_name)
+        logger.setLevel(extra_config.level)
+        logger.propagate = extra_config.propagate
         for handler in extra_config.handlers:
             if not config["incremental"]:
                 logger.addHandler(handler)
-            if logger.level == logging.NOTSET:
-                logger.setLevel(extra_config.level)
-            logger.propagate = extra_config.propagate
 
     PROCESS_LOGGING_CONFIG = config