[bgp] Add dependency in bgpcfgd (sonic-net#19088)

Why I did it
These 2 dependencies were removed by sonic-net#18764 and sonic-net#18727 for decoupling hard dependency between Loopback IPv4 address and BGP.
Actually, these dependencies are to make sure existence of Loopback interface, no need to remove.

Work item tracking
Microsoft ADO (number only): 28210625
How I did it
Add dependency back

How to verify it
UT passed.

src/sonic-bgpcfgd/bgpcfgd/managers_bgp.py

@@ -106,6 +106,7 @@ def __init__(self, common_objs, db_name, table_name, peer_type, check_neig_meta)
 
         deps = [
             ("CONFIG_DB", swsscommon.CFG_DEVICE_METADATA_TABLE_NAME, "localhost/bgp_asn"),
+            ("CONFIG_DB", swsscommon.CFG_LOOPBACK_INTERFACE_TABLE_NAME, "Loopback0"),
             ("CONFIG_DB", swsscommon.CFG_BGP_DEVICE_GLOBAL_TABLE_NAME, "tsa_enabled"),
             ("LOCAL", "local_addresses", ""),
             ("LOCAL", "interfaces", ""),
@@ -128,6 +129,9 @@ def __init__(self, common_objs, db_name, table_name, peer_type, check_neig_meta)
         if self.check_deployment_id:
             deps.append(("CONFIG_DB", swsscommon.CFG_DEVICE_METADATA_TABLE_NAME, "localhost/deployment_id"))
 
+        if self.peer_type == 'internal':
+            deps.append(("CONFIG_DB", swsscommon.CFG_LOOPBACK_INTERFACE_TABLE_NAME, "Loopback4096"))
+
         super(BGPPeerMgrBase, self).__init__(
             common_objs,
             deps,