deprecate timezones.json (#10311)

tests/test-config.json

@@ -396,8 +396,5 @@
     "DisplaySettings": {
         "CustomUrlSchemes": [],
         "ExperimentalTimezone": false
-    },
-    "TimezoneSettings": {
-        "SupportedTimezonesPath": "timezones.json"
     }
-}
+}