chore: disable renovate for grpc and guava versions (#2618)

This is a temporarily change for lts., will revert when Beam is
released.
Set [`enabled to
false](https://docs.renovatebot.com/configuration-options/#enabled) to
disable Renovate for these two grpc and guava.
currently grpc version is 1.62.2 (updated in
[pr](https://github.com/googleapis/sdk-platform-java/pull/2506/files)),
guava is 33.1.0-jre (updated in
[pr](https://github.com/googleapis/sdk-platform-java/pull/2574/files))

renovate.json

@@ -84,7 +84,8 @@
       "matchPackagePatterns": [
         "^com.google.guava:"
       ],
-      "versioning": "docker"
+      "versioning": "docker",
+      "enabled": false
     },
     {
       "matchPackagePatterns": [
@@ -148,7 +149,8 @@
       "matchPackagePatterns": [
         "^io.grpc"
       ],
-      "groupName": "gRPC dependencies"
+      "groupName": "gRPC dependencies",
+      "enabled": false
     },
     {
       "matchPackagePatterns": [