fix: Correct github action paths for v1.86.0 update

The recent renovate update to v1.86.0 in #2377 incorrectly pointed to a subfolder of google-cloud-java instead of the correct sdk-platform-java repository, breaking the hermetic library generation and unmanaged dependency check jobs. This restores the correct path.

Author: MarkDuckworth

.github/workflows/hermetic_library_generation.yaml

@@ -37,7 +37,7 @@ jobs:
       with:
         fetch-depth: 0
         token: ${{ secrets.CLOUD_JAVA_BOT_GITHUB_TOKEN }}
-    - uses: googleapis/google-cloud-java/sdk-platform-java/.github/scripts@v1.86.0
+    - uses: googleapis/sdk-platform-java/.github/scripts@v1.86.0
       if: env.SHOULD_RUN == 'true'
       with:
         base_ref: ${{ github.base_ref }}

.github/workflows/unmanaged-dependency-check.yaml

@@ -14,6 +14,6 @@ jobs:
       shell: bash
       run: .kokoro/build.sh
     - name: Unmanaged dependency check
-      uses: googleapis/google-cloud-java/sdk-platform-java/java-shared-dependencies/unmanaged-dependency-check@v1.86.0
+      uses: googleapis/sdk-platform-java/java-shared-dependencies/unmanaged-dependency-check@v1.86.0
       with:
         bom-path: google-cloud-firestore-bom/pom.xml