Correct @cf/google/gemma-3-12b-it context window to 80k (#21751)

Author: ashishdatta

src/content/workers-ai-models/gemma-3-12b-it.json

@@ -13,7 +13,7 @@
     "properties": [
         {
             "property_id": "context_window",
-            "value": "1280000"
+            "value": "80000"
         },
         {
             "property_id": "price",