Automerge: [CI][Github] Fix Premerge Summary for Build Failures (#153076)

We were passing the wrong directory to `generate_test_report_github.py`,
so no logs actually got passed there. This fixes that and ensures that
the logs are uploaded as artifacts to enable future debugging.

Author: boomanaiden154

.ci/utils.sh

@@ -26,14 +26,15 @@ function at-exit {
   mkdir -p artifacts
   sccache --show-stats >> artifacts/sccache_stats.txt
   cp "${BUILD_DIR}"/.ninja_log artifacts/.ninja_log
+  cp "${MONOREPO_ROOT}"/*.log artifacts/ || :
   cp "${BUILD_DIR}"/test-results.*.xml artifacts/ || :
 
   # If building fails there will be no results files.
   shopt -s nullglob
 
   if [[ "$GITHUB_STEP_SUMMARY" != "" ]]; then
     python "${MONOREPO_ROOT}"/.ci/generate_test_report_github.py \
-      $retcode "${BUILD_DIR}"/test-results.*.xml "${BUILD_DIR}"/ninja*.log \
+      $retcode "${BUILD_DIR}"/test-results.*.xml "${MONOREPO_ROOT}"/ninja*.log \
       >> $GITHUB_STEP_SUMMARY
   fi
 }