chore: hermetic build to manage the graalvm presubmit image versions

googleapis/sdk-platform-java#3800

Author: diegomarquezp

renovate.json

@@ -16,8 +16,7 @@
     {
       "customType": "regex",
       "fileMatch": [
-        "^.kokoro/continuous/graalvm-native.*.cfg$",
-        "^.kokoro/presubmit/graalvm-native.*.cfg$"
+        "^.kokoro/continuous/graalvm-native.*.cfg$"
       ],
       "matchStrings": [
         "value: \"gcr.io/cloud-devrel-public-resources/graalvm.*:(?<currentValue>.*?)\""