fix: Update renovate config check template to use npx (#12865)

This PR updates the renovate config check workflow template to use npx
instead of global installation, avoiding issues with missing modules.
Renovate.json template is also updated to use the
google-cloud-shared-dependencies Git tag in the google-cloud-java
repository.

Until this template change is propagated to the split repositories, the
repositories with hermetic build automation reverts the change.

b/504692883

Author: suztomo

sdk-platform-java/hermetic_build/library_generation/owlbot/templates/java_library/.github/workflows/renovate_config_check.yaml

@@ -4,6 +4,7 @@ on:
   pull_request:
     paths:
       - 'renovate.json'
+      - '.github/workflows/renovate_config_check.yaml'
 
 jobs:
   renovate_bot_config_validation:
@@ -18,8 +19,6 @@ jobs:
       with:
         node-version: '22'
 
-    - name: Install Renovate and Config Validator
+    - name: Run Renovate Config Validator
       run: |
-        npm install -g npm@latest
-        npm install --global renovate
-        renovate-config-validator
+        npx --package renovate@43.136.0 renovate-config-validator

sdk-platform-java/hermetic_build/library_generation/owlbot/templates/java_library/renovate.json

@@ -29,9 +29,9 @@
         "^.github/workflows/unmanaged_dependency_check.yaml$"
       ],
       "matchStrings": [
-        "uses: googleapis/google-cloud-java/sdk-platform-java/java-shared-dependencies/unmanaged-dependency-check@v(?<currentValue>.+?)\\n"
+        "uses: googleapis/google-cloud-java/sdk-platform-java/java-shared-dependencies/unmanaged-dependency-check@google-cloud-shared-dependencies/v(?<currentValue>.+?)\\n"
       ],
-      "depNameTemplate": "com.google.cloud:gapic-libraries-bom",
+      "depNameTemplate": "com.google.cloud:google-cloud-shared-dependencies",
       "datasourceTemplate": "maven"
     }
   ],