fix: sync realtime model literals in realtime config (#2535)

Author: seratch

src/agents/realtime/config.py

@@ -19,15 +19,17 @@
 RealtimeModelName: TypeAlias = Union[
     Literal[
         "gpt-realtime",
+        "gpt-realtime-1.5",
         "gpt-realtime-2025-08-28",
         "gpt-4o-realtime-preview",
-        "gpt-4o-mini-realtime-preview",
-        "gpt-4o-realtime-preview-2025-06-03",
-        "gpt-4o-realtime-preview-2024-12-17",
         "gpt-4o-realtime-preview-2024-10-01",
+        "gpt-4o-realtime-preview-2024-12-17",
+        "gpt-4o-realtime-preview-2025-06-03",
+        "gpt-4o-mini-realtime-preview",
         "gpt-4o-mini-realtime-preview-2024-12-17",
         "gpt-realtime-mini",
         "gpt-realtime-mini-2025-10-06",
+        "gpt-realtime-mini-2025-12-15",
     ],
     str,
 ]