Ensure a unique ID for supply routes.

List indexes are not a reliable list key unless the list is static.
Indexes will be reused when games are loaded, which prevents the state
from updating reliably.

Fixes https://github.com/dcs-liberation/dcs_liberation/issues/2167

client/src/api/_liberationApi.ts

@@ -428,6 +428,7 @@ export type Tgo = {
   sidc: string;
 };
 export type SupplyRoute = {
+  id: string;
   points: LatLng[];
   front_active: boolean;
   is_sea: boolean;