Update publish unit test results (#6344)

Per [b/370923997](https://b.corp.google.com/issues/370923997),

This updates our `publish-unit-test-result` action usage to `2.9.0`
instead of the old versions we were using. This should help avoid the
secondary rate limits we've been hitting as of late.

Author: daymxn

.github/workflows/build-src-check.yml

@@ -26,7 +26,7 @@ jobs:
         run: |
           ./gradlew -b buildSrc/build.gradle.kts -PenablePluginTests=true check
       - name: Publish Test Results
-        uses: EnricoMi/publish-unit-test-result-action@b9f6c61d965bcaa18acc02d6daf706373a448f02
+        uses: EnricoMi/publish-unit-test-result-action@82082dac68ad6a19d980f8ce817e108b9f496c2a
         with:
           files: "**/build/test-results/**/*.xml"
           check_name: "buildSrc Test Results"

.github/workflows/ci_tests.yml

@@ -172,6 +172,6 @@ jobs:
           path: artifacts
 
       - name: Publish Test Results
-        uses: EnricoMi/publish-unit-test-result-action@v1
+        uses: EnricoMi/publish-unit-test-result-action@82082dac68ad6a19d980f8ce817e108b9f496c2a
         with:
           files: "artifacts/**/*.xml"