Dataplane: feature toggle cleanup dataplane frontend fallback (#113542)

* remove feature toggle dataplaneFrontendFallback because GA

* remove feature toggle logic

* fix import

* fix toggle ownership from merging main

* merge main

* fix extra feature toggle

pkg/services/featuremgmt/toggles_gen.json

@@ -1258,7 +1258,8 @@
       "metadata": {
         "name": "dataplaneFrontendFallback",
         "resourceVersion": "1753448760331",
-        "creationTimestamp": "2023-04-07T21:13:19Z"
+        "creationTimestamp": "2023-04-07T21:13:19Z",
+        "deletionTimestamp": "2025-11-06T17:39:31Z"
       },
       "spec": {
         "description": "Support dataplane contract field name change for transformations and field name matchers where the name is different",
@@ -4088,6 +4089,7 @@
         "name": "timeRangePan",
         "resourceVersion": "1762290731154",
         "creationTimestamp": "2025-10-24T19:49:53Z",
+        "deletionTimestamp": "2025-11-06T17:39:31Z",
         "annotations": {
           "grafana.app/updatedTimestamp": "2025-11-04 21:12:11.154822 +0000 UTC"
         }