Fix DBConfig not initialize issue in pfcwd (#2238) (#2372)

#### What I did
Fix pfcwd connect DB with exception issue: sonic-net/sonic-buildimage#11269

pfcwd implicit depends on InterfaceAliasConverter() to initialize DB config, however following PR change InterfaceAliasConverter() behavior to lazy initialize, then pfcwd failed when try connect to DB without initialize DB config:

#2183

#### How I did it
Load  DB config in pfcwd.

#### How to verify it
Pass all UT.

Co-authored-by: Hua Liu <[email protected]>

Author: gechiang

pfcwd/main.py

@@ -9,6 +9,7 @@
 from tabulate import tabulate
 from utilities_common import multi_asic as multi_asic_util
 from utilities_common import constants
+from utilities_common.general import load_db_config
 from sonic_py_common import logger
 
 SYSLOG_IDENTIFIER = "config"
@@ -62,7 +63,7 @@
 @click.group()
 def cli():
     """ SONiC PFC Watchdog """
-
+    load_db_config()
 
 def get_all_queues(db, namespace=None, display=constants.DISPLAY_ALL):
     queue_names = db.get_all(db.COUNTERS_DB, 'COUNTERS_QUEUE_NAME_MAP')