raylib ui: assert system time valid (#36486)

* assert system time valid

* nl

selfdrive/ui/lib/api_helpers.py

@@ -1,12 +1,16 @@
 import time
 from functools import lru_cache
 from openpilot.common.api import Api
+from openpilot.common.time_helpers import system_time_valid
 
 TOKEN_EXPIRY_HOURS = 2
 
 
 @lru_cache(maxsize=1)
 def _get_token(dongle_id: str, t: int):
+  if not system_time_valid():
+    raise RuntimeError("System time is not valid, cannot generate token")
+
   return Api(dongle_id).get_token(expiry_hours=TOKEN_EXPIRY_HOURS)