Add dependency for tsa_enabled flag before populating peer config and…

… bringing up BGP (#18556)

Why I did it
Ensure BGP peer bring-up and route advertisements are done only after checking TSA status during reload

Work item tracking
Microsoft ADO (number only): 27171112
How I did it
Add dependency on tsa_enabled flag before peer configuration

How to verify it
Validate that the BGP session bring up is not complete until tsa_enabled flag is populated.
Ensure no traffic is drawn to the device when in TSA and reboot with BGP unshut.

src/sonic-bgpcfgd/bgpcfgd/managers_bgp.py

@@ -107,6 +107,7 @@ 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", ""),
         ]