fix: Undeprecate 'network' in schema route definition (#5072)

It is passed through to our v1 schema from OpenStack network_data.json

Fixes GH-5051

cloudinit/config/schemas/schema-network-config-v1.json

@@ -450,10 +450,7 @@
         },
         "network": {
           "type": "string",
-          "description": "IPv4 network address with CIDR netmask notation or IPv6 with prefix length. Alias for ``destination`` and only read when ``destination`` key is absent.",
-          "deprecated": true,
-          "deprecated_version": "23.3",
-          "deprecated_description": "Use ``destination`` instead."
+          "description": "IPv4 network address with CIDR netmask notation or IPv6 with prefix length. Alias for ``destination`` and only read when ``destination`` key is absent. This exists for OpenStack support. OpenStack route definitions are passed through to v1 config and OpenStack's ``network_data.json`` uses ``network`` instead of ``destination``."
         },
         "destination": {
           "type": "string",