Remove legacy source provider sync path

dns_sync/config.py

@@ -97,8 +97,6 @@ def env_bool(name: str, default: bool) -> bool:
 
 @dataclass(frozen=True)
 class AppConfig:
-    source_name: str
-    provider_name: str
     npm_endpoints: tuple[Endpoint, ...]
     proxy_ip: str
     proxy_api_port: int
@@ -118,9 +116,6 @@ class AppConfig:
 
     @classmethod
     def from_env(cls, include_disabled: bool = False) -> "AppConfig":
-        source_name = os.getenv("PROXY", "npm").strip().lower()
-        provider_name = os.getenv("DNS_PROVIDER", "verizon").strip().lower()
-
         try:
             port = int(os.getenv("PROXY_API_PORT", "81"))
         except ValueError as exc:
@@ -185,8 +180,6 @@ class AppConfig:
             )
 
         return cls(
-            source_name=source_name,
-            provider_name=provider_name,
             npm_endpoints=npm_endpoints,
             proxy_ip=proxy_ip,
             proxy_api_port=port,